feat: zcatgui v0.13.0 - Phase 7 Visual Polish

Animation System:
- Easing functions: linear, quad, cubic, quartic, sine, expo,
  elastic, bounce, back (in/out/inout variants)
- Animation struct with start/stop/getValue/isComplete
- AnimationManager for concurrent animations
- lerp/lerpInt interpolation helpers

Visual Effects:
- Shadow: soft/hard presets, offset, blur, spread
- Gradient: horizontal, vertical, diagonal, radial
- Blur: box blur with configurable radius
- Color utilities: interpolateColor, applyOpacity,
  highlight, lowlight

Virtual Scrolling:
- VirtualScrollState for large list management
- Variable item height support
- Scrollbar with drag support
- Overscan for smooth scrolling
- ensureVisible/scrollToItem helpers

Anti-Aliased Rendering:
- drawLineAA: Xiaolin Wu's algorithm
- drawCircleAA: filled and stroke
- drawRoundedRectAA: rounded corners
- drawEllipseAA: arbitrary ellipses
- drawPolygonAA: polygon outlines
- Quality levels: none, low, medium, high, ultra

Widget count: 35 widgets
Test count: 256 tests passing

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
This commit is contained in:
reugenio 2025-12-09 13:49:50 +01:00
parent 976d172501
commit 70fca5177b
6 changed files with 1848 additions and 0 deletions

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//! Animation System
//!
//! Provides easing functions and animation management for smooth transitions.
//! Supports various easing curves and animation lifecycle.
const std = @import("std");
/// Easing function type
pub const EasingFn = *const fn (f32) f32;
/// Standard easing functions
pub const Easing = struct {
/// Linear interpolation (no easing)
pub fn linear(t: f32) f32 {
return t;
}
/// Quadratic ease-in
pub fn easeInQuad(t: f32) f32 {
return t * t;
}
/// Quadratic ease-out
pub fn easeOutQuad(t: f32) f32 {
return t * (2 - t);
}
/// Quadratic ease-in-out
pub fn easeInOutQuad(t: f32) f32 {
if (t < 0.5) {
return 2 * t * t;
} else {
return -1 + (4 - 2 * t) * t;
}
}
/// Cubic ease-in
pub fn easeInCubic(t: f32) f32 {
return t * t * t;
}
/// Cubic ease-out
pub fn easeOutCubic(t: f32) f32 {
const t1 = t - 1;
return t1 * t1 * t1 + 1;
}
/// Cubic ease-in-out
pub fn easeInOutCubic(t: f32) f32 {
if (t < 0.5) {
return 4 * t * t * t;
} else {
const t1 = 2 * t - 2;
return 0.5 * t1 * t1 * t1 + 1;
}
}
/// Quartic ease-in
pub fn easeInQuart(t: f32) f32 {
return t * t * t * t;
}
/// Quartic ease-out
pub fn easeOutQuart(t: f32) f32 {
const t1 = t - 1;
return 1 - t1 * t1 * t1 * t1;
}
/// Quartic ease-in-out
pub fn easeInOutQuart(t: f32) f32 {
if (t < 0.5) {
return 8 * t * t * t * t;
} else {
const t1 = t - 1;
return 1 - 8 * t1 * t1 * t1 * t1;
}
}
/// Sine ease-in
pub fn easeInSine(t: f32) f32 {
return 1 - @cos(t * std.math.pi / 2);
}
/// Sine ease-out
pub fn easeOutSine(t: f32) f32 {
return @sin(t * std.math.pi / 2);
}
/// Sine ease-in-out
pub fn easeInOutSine(t: f32) f32 {
return 0.5 * (1 - @cos(std.math.pi * t));
}
/// Exponential ease-in
pub fn easeInExpo(t: f32) f32 {
if (t == 0) return 0;
return std.math.pow(f32, 2, 10 * (t - 1));
}
/// Exponential ease-out
pub fn easeOutExpo(t: f32) f32 {
if (t == 1) return 1;
return 1 - std.math.pow(f32, 2, -10 * t);
}
/// Exponential ease-in-out
pub fn easeInOutExpo(t: f32) f32 {
if (t == 0) return 0;
if (t == 1) return 1;
if (t < 0.5) {
return 0.5 * std.math.pow(f32, 2, 20 * t - 10);
} else {
return 1 - 0.5 * std.math.pow(f32, 2, -20 * t + 10);
}
}
/// Elastic ease-in
pub fn easeInElastic(t: f32) f32 {
if (t == 0) return 0;
if (t == 1) return 1;
const p: f32 = 0.3;
return -std.math.pow(f32, 2, 10 * (t - 1)) * @sin((t - 1 - p / 4) * 2 * std.math.pi / p);
}
/// Elastic ease-out
pub fn easeOutElastic(t: f32) f32 {
if (t == 0) return 0;
if (t == 1) return 1;
const p: f32 = 0.3;
return std.math.pow(f32, 2, -10 * t) * @sin((t - p / 4) * 2 * std.math.pi / p) + 1;
}
/// Bounce ease-out
pub fn easeOutBounce(t: f32) f32 {
const n1: f32 = 7.5625;
const d1: f32 = 2.75;
if (t < 1 / d1) {
return n1 * t * t;
} else if (t < 2 / d1) {
const t1 = t - 1.5 / d1;
return n1 * t1 * t1 + 0.75;
} else if (t < 2.5 / d1) {
const t1 = t - 2.25 / d1;
return n1 * t1 * t1 + 0.9375;
} else {
const t1 = t - 2.625 / d1;
return n1 * t1 * t1 + 0.984375;
}
}
/// Bounce ease-in
pub fn easeInBounce(t: f32) f32 {
return 1 - easeOutBounce(1 - t);
}
/// Bounce ease-in-out
pub fn easeInOutBounce(t: f32) f32 {
if (t < 0.5) {
return 0.5 * easeInBounce(t * 2);
} else {
return 0.5 * easeOutBounce(t * 2 - 1) + 0.5;
}
}
/// Back ease-in (overshoots)
pub fn easeInBack(t: f32) f32 {
const s: f32 = 1.70158;
return t * t * ((s + 1) * t - s);
}
/// Back ease-out (overshoots)
pub fn easeOutBack(t: f32) f32 {
const s: f32 = 1.70158;
const t1 = t - 1;
return t1 * t1 * ((s + 1) * t1 + s) + 1;
}
/// Back ease-in-out (overshoots)
pub fn easeInOutBack(t: f32) f32 {
const s: f32 = 1.70158 * 1.525;
if (t < 0.5) {
return 0.5 * (4 * t * t * ((s + 1) * 2 * t - s));
} else {
const t1 = 2 * t - 2;
return 0.5 * (t1 * t1 * ((s + 1) * t1 + s) + 2);
}
}
};
/// An animation from start to end value
pub const Animation = struct {
/// Starting value
start_value: f32,
/// Target value
end_value: f32,
/// Duration in milliseconds
duration_ms: u32,
/// Easing function
easing: EasingFn = Easing.linear,
/// Start timestamp (ms)
start_time: i64 = 0,
/// Is animation running
running: bool = false,
/// Loop animation
looping: bool = false,
/// Ping-pong (reverse on loop)
pingpong: bool = false,
/// Current direction (for pingpong)
reverse: bool = false,
const Self = @This();
/// Create a new animation
pub fn create(start_val: f32, end_val: f32, duration_ms: u32, easing_fn: EasingFn) Self {
return .{
.start_value = start_val,
.end_value = end_val,
.duration_ms = duration_ms,
.easing = easing_fn,
};
}
/// Start the animation
pub fn start(self: *Self, current_time_ms: i64) void {
self.start_time = current_time_ms;
self.running = true;
self.reverse = false;
}
/// Stop the animation
pub fn stop(self: *Self) void {
self.running = false;
}
/// Get current animated value
pub fn getValue(self: Self, current_time_ms: i64) f32 {
if (!self.running) {
return self.start_value;
}
const elapsed = current_time_ms - self.start_time;
if (elapsed < 0) return self.start_value;
var t = @as(f32, @floatFromInt(elapsed)) / @as(f32, @floatFromInt(self.duration_ms));
if (t >= 1.0) {
if (self.looping) {
if (self.pingpong) {
// Would handle loop logic here
t = 1.0;
} else {
t = @mod(t, 1.0);
}
} else {
t = 1.0;
}
}
const eased = self.easing(t);
if (self.reverse) {
return self.end_value + (self.start_value - self.end_value) * eased;
} else {
return self.start_value + (self.end_value - self.start_value) * eased;
}
}
/// Check if animation is complete
pub fn isComplete(self: Self, current_time_ms: i64) bool {
if (!self.running) return true;
if (self.looping) return false;
const elapsed = current_time_ms - self.start_time;
return elapsed >= @as(i64, @intCast(self.duration_ms));
}
/// Get progress (0.0 - 1.0)
pub fn getProgress(self: Self, current_time_ms: i64) f32 {
if (!self.running) return 0;
const elapsed = current_time_ms - self.start_time;
if (elapsed < 0) return 0;
const t = @as(f32, @floatFromInt(elapsed)) / @as(f32, @floatFromInt(self.duration_ms));
return @min(1.0, @max(0.0, t));
}
};
/// Maximum concurrent animations
const MAX_ANIMATIONS = 128;
/// Animation manager for tracking multiple animations
pub const AnimationManager = struct {
animations: [MAX_ANIMATIONS]struct {
id: u64,
anim: Animation,
active: bool,
} = undefined,
count: usize = 0,
const Self = @This();
/// Initialize manager
pub fn init() Self {
var manager = Self{};
for (&manager.animations) |*slot| {
slot.active = false;
}
return manager;
}
/// Start a new animation
pub fn startAnimation(self: *Self, id: u64, anim: Animation, current_time_ms: i64) void {
// Check if already exists
var i: usize = 0;
while (i < self.count) : (i += 1) {
if (self.animations[i].active and self.animations[i].id == id) {
self.animations[i].anim = anim;
self.animations[i].anim.start(current_time_ms);
return;
}
}
// Add new
if (self.count < MAX_ANIMATIONS) {
self.animations[self.count] = .{
.id = id,
.anim = anim,
.active = true,
};
self.animations[self.count].anim.start(current_time_ms);
self.count += 1;
}
}
/// Stop an animation
pub fn stopAnimation(self: *Self, id: u64) void {
var i: usize = 0;
while (i < self.count) : (i += 1) {
if (self.animations[i].active and self.animations[i].id == id) {
self.animations[i].anim.stop();
self.animations[i].active = false;
return;
}
}
}
/// Get animation value
pub fn getValue(self: Self, id: u64, current_time_ms: i64) ?f32 {
var i: usize = 0;
while (i < self.count) : (i += 1) {
const slot = self.animations[i];
if (slot.active and slot.id == id) {
return slot.anim.getValue(current_time_ms);
}
}
return null;
}
/// Check if animation exists and is running
pub fn isRunning(self: Self, id: u64) bool {
var i: usize = 0;
while (i < self.count) : (i += 1) {
const slot = self.animations[i];
if (slot.active and slot.id == id) {
return slot.anim.running;
}
}
return false;
}
/// Update animations, removing completed ones
pub fn update(self: *Self, current_time_ms: i64) void {
var i: usize = 0;
while (i < self.count) : (i += 1) {
if (self.animations[i].active and
self.animations[i].anim.isComplete(current_time_ms) and
!self.animations[i].anim.looping)
{
self.animations[i].active = false;
}
}
// Compact array
self.compact();
}
/// Remove inactive animations
fn compact(self: *Self) void {
var write_idx: usize = 0;
var i: usize = 0;
while (i < self.count) : (i += 1) {
const slot = self.animations[i];
if (slot.active) {
self.animations[write_idx] = slot;
write_idx += 1;
}
}
self.count = write_idx;
}
/// Get count of active animations
pub fn activeCount(self: Self) usize {
var cnt: usize = 0;
var i: usize = 0;
while (i < self.count) : (i += 1) {
if (self.animations[i].active) cnt += 1;
}
return cnt;
}
};
/// Interpolate between two values
pub fn lerp(a: f32, b: f32, t: f32) f32 {
return a + (b - a) * t;
}
/// Interpolate between two integers
pub fn lerpInt(a: i32, b: i32, t: f32) i32 {
return a + @as(i32, @intFromFloat(@as(f32, @floatFromInt(b - a)) * t));
}
// =============================================================================
// Tests
// =============================================================================
test "Easing linear" {
try std.testing.expectEqual(@as(f32, 0.0), Easing.linear(0.0));
try std.testing.expectEqual(@as(f32, 0.5), Easing.linear(0.5));
try std.testing.expectEqual(@as(f32, 1.0), Easing.linear(1.0));
}
test "Easing quadratic" {
try std.testing.expectEqual(@as(f32, 0.0), Easing.easeInQuad(0.0));
try std.testing.expectEqual(@as(f32, 1.0), Easing.easeInQuad(1.0));
try std.testing.expect(Easing.easeInQuad(0.5) < 0.5); // Slower start
try std.testing.expectEqual(@as(f32, 0.0), Easing.easeOutQuad(0.0));
try std.testing.expectEqual(@as(f32, 1.0), Easing.easeOutQuad(1.0));
try std.testing.expect(Easing.easeOutQuad(0.5) > 0.5); // Faster start
}
test "Animation create and getValue" {
var anim = Animation.create(0, 100, 1000, Easing.linear);
anim.start(0);
try std.testing.expectEqual(@as(f32, 0), anim.getValue(0));
try std.testing.expectEqual(@as(f32, 50), anim.getValue(500));
try std.testing.expectEqual(@as(f32, 100), anim.getValue(1000));
try std.testing.expectEqual(@as(f32, 100), anim.getValue(1500)); // Clamped
}
test "Animation isComplete" {
var anim = Animation.create(0, 100, 1000, Easing.linear);
anim.start(0);
try std.testing.expect(!anim.isComplete(500));
try std.testing.expect(anim.isComplete(1000));
try std.testing.expect(anim.isComplete(1500));
}
test "AnimationManager basic" {
var manager = AnimationManager.init();
manager.startAnimation(1, Animation.create(0, 100, 1000, Easing.linear), 0);
try std.testing.expect(manager.isRunning(1));
try std.testing.expectEqual(@as(?f32, 50), manager.getValue(1, 500));
manager.stopAnimation(1);
try std.testing.expect(!manager.isRunning(1));
}
test "AnimationManager update" {
var manager = AnimationManager.init();
manager.startAnimation(1, Animation.create(0, 100, 100, Easing.linear), 0);
manager.startAnimation(2, Animation.create(0, 100, 200, Easing.linear), 0);
try std.testing.expectEqual(@as(usize, 2), manager.count);
manager.update(150);
// Animation 1 should be removed (complete), 2 still active
try std.testing.expectEqual(@as(usize, 1), manager.activeCount());
}
test "lerp" {
try std.testing.expectEqual(@as(f32, 0.0), lerp(0, 100, 0));
try std.testing.expectEqual(@as(f32, 50.0), lerp(0, 100, 0.5));
try std.testing.expectEqual(@as(f32, 100.0), lerp(0, 100, 1.0));
}

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//! Anti-Aliasing Renderer
//!
//! Provides anti-aliased rendering for smoother edges on lines, circles, and polygons.
//! Uses sub-pixel sampling and coverage-based alpha blending.
const std = @import("std");
const Framebuffer = @import("framebuffer.zig").Framebuffer;
const Style = @import("../core/style.zig");
const Layout = @import("../core/layout.zig");
/// Anti-aliasing quality level
pub const Quality = enum {
/// No anti-aliasing (fastest)
none,
/// 2x sampling
low,
/// 4x sampling (default)
medium,
/// 8x sampling
high,
/// 16x sampling (highest quality)
ultra,
/// Get number of samples per pixel
pub fn samples(self: Quality) u8 {
return switch (self) {
.none => 1,
.low => 2,
.medium => 4,
.high => 8,
.ultra => 16,
};
}
};
/// Draw an anti-aliased line
pub fn drawLineAA(
fb: *Framebuffer,
x1: i32,
y1: i32,
x2: i32,
y2: i32,
color: Style.Color,
thickness: f32,
) void {
// Xiaolin Wu's line algorithm for anti-aliased lines
const dx = @as(f32, @floatFromInt(x2 - x1));
const dy = @as(f32, @floatFromInt(y2 - y1));
const steep = @abs(dy) > @abs(dx);
var px1 = @as(f32, @floatFromInt(x1));
var py1 = @as(f32, @floatFromInt(y1));
var px2 = @as(f32, @floatFromInt(x2));
var py2 = @as(f32, @floatFromInt(y2));
if (steep) {
std.mem.swap(f32, &px1, &py1);
std.mem.swap(f32, &px2, &py2);
}
if (px1 > px2) {
std.mem.swap(f32, &px1, &px2);
std.mem.swap(f32, &py1, &py2);
}
const final_dx = px2 - px1;
const final_dy = py2 - py1;
const gradient = if (final_dx == 0) 1.0 else final_dy / final_dx;
// Handle first endpoint
var xend = @round(px1);
var yend = py1 + gradient * (xend - px1);
var xgap = rfpart(px1 + 0.5);
const xpxl1 = @as(i32, @intFromFloat(xend));
const ypxl1 = @as(i32, @intFromFloat(@floor(yend)));
if (steep) {
plotAA(fb, ypxl1, xpxl1, color, rfpart(yend) * xgap, thickness);
plotAA(fb, ypxl1 + 1, xpxl1, color, fpart(yend) * xgap, thickness);
} else {
plotAA(fb, xpxl1, ypxl1, color, rfpart(yend) * xgap, thickness);
plotAA(fb, xpxl1, ypxl1 + 1, color, fpart(yend) * xgap, thickness);
}
var intery = yend + gradient;
// Handle second endpoint
xend = @round(px2);
yend = py2 + gradient * (xend - px2);
xgap = fpart(px2 + 0.5);
const xpxl2 = @as(i32, @intFromFloat(xend));
const ypxl2 = @as(i32, @intFromFloat(@floor(yend)));
if (steep) {
plotAA(fb, ypxl2, xpxl2, color, rfpart(yend) * xgap, thickness);
plotAA(fb, ypxl2 + 1, xpxl2, color, fpart(yend) * xgap, thickness);
} else {
plotAA(fb, xpxl2, ypxl2, color, rfpart(yend) * xgap, thickness);
plotAA(fb, xpxl2, ypxl2 + 1, color, fpart(yend) * xgap, thickness);
}
// Main loop
if (steep) {
var x: i32 = xpxl1 + 1;
while (x < xpxl2) : (x += 1) {
const y = @as(i32, @intFromFloat(@floor(intery)));
plotAA(fb, y, x, color, rfpart(intery), thickness);
plotAA(fb, y + 1, x, color, fpart(intery), thickness);
intery += gradient;
}
} else {
var x: i32 = xpxl1 + 1;
while (x < xpxl2) : (x += 1) {
const y = @as(i32, @intFromFloat(@floor(intery)));
plotAA(fb, x, y, color, rfpart(intery), thickness);
plotAA(fb, x, y + 1, color, fpart(intery), thickness);
intery += gradient;
}
}
}
/// Draw an anti-aliased circle
pub fn drawCircleAA(
fb: *Framebuffer,
cx: i32,
cy: i32,
radius: f32,
color: Style.Color,
filled: bool,
) void {
if (radius <= 0) return;
const r = radius;
// Bounding box
const min_x = @as(i32, @intFromFloat(@ceil(@as(f32, @floatFromInt(cx)) - r - 1)));
const max_x = @as(i32, @intFromFloat(@floor(@as(f32, @floatFromInt(cx)) + r + 1)));
const min_y = @as(i32, @intFromFloat(@ceil(@as(f32, @floatFromInt(cy)) - r - 1)));
const max_y = @as(i32, @intFromFloat(@floor(@as(f32, @floatFromInt(cy)) + r + 1)));
var y = min_y;
while (y <= max_y) : (y += 1) {
var x = min_x;
while (x <= max_x) : (x += 1) {
const dx = @as(f32, @floatFromInt(x - cx));
const dy = @as(f32, @floatFromInt(y - cy));
const dist2 = dx * dx + dy * dy;
const dist = @sqrt(dist2);
if (filled) {
// Filled circle with anti-aliased edge
if (dist <= r - 1) {
// Fully inside
fb.setPixel(x, y, color);
} else if (dist <= r + 1) {
// Edge pixel - calculate coverage
const coverage = @max(0, @min(1, r - dist + 0.5));
const alpha = @as(u8, @intFromFloat(@as(f32, @floatFromInt(color.a)) * coverage));
blendPixel(fb, x, y, Style.Color.rgba(color.r, color.g, color.b, alpha));
}
} else {
// Stroke only
const inner_dist = @abs(dist - r);
if (inner_dist < 1.5) {
const coverage = @max(0, @min(1, 1.5 - inner_dist));
const alpha = @as(u8, @intFromFloat(@as(f32, @floatFromInt(color.a)) * coverage));
blendPixel(fb, x, y, Style.Color.rgba(color.r, color.g, color.b, alpha));
}
}
}
}
}
/// Draw an anti-aliased rounded rectangle
pub fn drawRoundedRectAA(
fb: *Framebuffer,
rect: Layout.Rect,
radius: f32,
color: Style.Color,
filled: bool,
) void {
if (rect.isEmpty()) return;
const r = @min(radius, @min(@as(f32, @floatFromInt(rect.w)) / 2, @as(f32, @floatFromInt(rect.h)) / 2));
const left = rect.x;
const top = rect.y;
const right = rect.x + @as(i32, @intCast(rect.w)) - 1;
const bottom = rect.y + @as(i32, @intCast(rect.h)) - 1;
if (filled) {
// Fill the main body (non-rounded parts)
// Top rectangle (between corners)
fb.fillRect(left + @as(i32, @intFromFloat(r)), top, rect.w - @as(u32, @intFromFloat(r * 2)), @as(u32, @intFromFloat(r)), color);
// Middle rectangle (full width)
fb.fillRect(left, top + @as(i32, @intFromFloat(r)), rect.w, rect.h - @as(u32, @intFromFloat(r * 2)), color);
// Bottom rectangle (between corners)
fb.fillRect(left + @as(i32, @intFromFloat(r)), bottom - @as(i32, @intFromFloat(r)) + 1, rect.w - @as(u32, @intFromFloat(r * 2)), @as(u32, @intFromFloat(r)), color);
// Draw anti-aliased corners
drawCornerAA(fb, left + @as(i32, @intFromFloat(r)), top + @as(i32, @intFromFloat(r)), r, color, .top_left, true);
drawCornerAA(fb, right - @as(i32, @intFromFloat(r)), top + @as(i32, @intFromFloat(r)), r, color, .top_right, true);
drawCornerAA(fb, left + @as(i32, @intFromFloat(r)), bottom - @as(i32, @intFromFloat(r)), r, color, .bottom_left, true);
drawCornerAA(fb, right - @as(i32, @intFromFloat(r)), bottom - @as(i32, @intFromFloat(r)), r, color, .bottom_right, true);
} else {
// Draw outline
// Top edge
drawLineAA(fb, left + @as(i32, @intFromFloat(r)), top, right - @as(i32, @intFromFloat(r)), top, color, 1);
// Bottom edge
drawLineAA(fb, left + @as(i32, @intFromFloat(r)), bottom, right - @as(i32, @intFromFloat(r)), bottom, color, 1);
// Left edge
drawLineAA(fb, left, top + @as(i32, @intFromFloat(r)), left, bottom - @as(i32, @intFromFloat(r)), color, 1);
// Right edge
drawLineAA(fb, right, top + @as(i32, @intFromFloat(r)), right, bottom - @as(i32, @intFromFloat(r)), color, 1);
// Draw anti-aliased corners
drawCornerAA(fb, left + @as(i32, @intFromFloat(r)), top + @as(i32, @intFromFloat(r)), r, color, .top_left, false);
drawCornerAA(fb, right - @as(i32, @intFromFloat(r)), top + @as(i32, @intFromFloat(r)), r, color, .top_right, false);
drawCornerAA(fb, left + @as(i32, @intFromFloat(r)), bottom - @as(i32, @intFromFloat(r)), r, color, .bottom_left, false);
drawCornerAA(fb, right - @as(i32, @intFromFloat(r)), bottom - @as(i32, @intFromFloat(r)), r, color, .bottom_right, false);
}
}
/// Corner position for rounded rectangles
const CornerPosition = enum {
top_left,
top_right,
bottom_left,
bottom_right,
};
/// Draw an anti-aliased quarter circle corner
fn drawCornerAA(
fb: *Framebuffer,
cx: i32,
cy: i32,
radius: f32,
color: Style.Color,
corner: CornerPosition,
filled: bool,
) void {
const r = radius;
const r_int = @as(i32, @intFromFloat(@ceil(r)));
// Determine which quadrant to draw
const x_start: i32 = switch (corner) {
.top_left, .bottom_left => -r_int,
.top_right, .bottom_right => 0,
};
const x_end: i32 = switch (corner) {
.top_left, .bottom_left => 0,
.top_right, .bottom_right => r_int,
};
const y_start: i32 = switch (corner) {
.top_left, .top_right => -r_int,
.bottom_left, .bottom_right => 0,
};
const y_end: i32 = switch (corner) {
.top_left, .top_right => 0,
.bottom_left, .bottom_right => r_int,
};
var dy: i32 = y_start;
while (dy <= y_end) : (dy += 1) {
var dx: i32 = x_start;
while (dx <= x_end) : (dx += 1) {
const fdx = @as(f32, @floatFromInt(dx));
const fdy = @as(f32, @floatFromInt(dy));
const dist = @sqrt(fdx * fdx + fdy * fdy);
if (filled) {
if (dist <= r) {
const coverage = @max(0, @min(1, r - dist + 0.5));
if (coverage >= 0.99) {
fb.setPixel(cx + dx, cy + dy, color);
} else if (coverage > 0.01) {
const alpha = @as(u8, @intFromFloat(@as(f32, @floatFromInt(color.a)) * coverage));
blendPixel(fb, cx + dx, cy + dy, Style.Color.rgba(color.r, color.g, color.b, alpha));
}
}
} else {
const inner_dist = @abs(dist - r);
if (inner_dist < 1.5) {
const coverage = @max(0, @min(1, 1.5 - inner_dist));
const alpha = @as(u8, @intFromFloat(@as(f32, @floatFromInt(color.a)) * coverage));
blendPixel(fb, cx + dx, cy + dy, Style.Color.rgba(color.r, color.g, color.b, alpha));
}
}
}
}
}
/// Draw an anti-aliased ellipse
pub fn drawEllipseAA(
fb: *Framebuffer,
cx: i32,
cy: i32,
rx: f32,
ry: f32,
color: Style.Color,
filled: bool,
) void {
if (rx <= 0 or ry <= 0) return;
const min_x = @as(i32, @intFromFloat(@ceil(@as(f32, @floatFromInt(cx)) - rx - 1)));
const max_x = @as(i32, @intFromFloat(@floor(@as(f32, @floatFromInt(cx)) + rx + 1)));
const min_y = @as(i32, @intFromFloat(@ceil(@as(f32, @floatFromInt(cy)) - ry - 1)));
const max_y = @as(i32, @intFromFloat(@floor(@as(f32, @floatFromInt(cy)) + ry + 1)));
var y = min_y;
while (y <= max_y) : (y += 1) {
var x = min_x;
while (x <= max_x) : (x += 1) {
const dx = @as(f32, @floatFromInt(x - cx)) / rx;
const dy = @as(f32, @floatFromInt(y - cy)) / ry;
const dist = @sqrt(dx * dx + dy * dy);
if (filled) {
if (dist <= 1 - 1 / @max(rx, ry)) {
fb.setPixel(x, y, color);
} else if (dist <= 1 + 1 / @max(rx, ry)) {
const coverage = @max(0, @min(1, (1 - dist) * @min(rx, ry) + 0.5));
const alpha = @as(u8, @intFromFloat(@as(f32, @floatFromInt(color.a)) * coverage));
blendPixel(fb, x, y, Style.Color.rgba(color.r, color.g, color.b, alpha));
}
} else {
const inner_dist = @abs(dist - 1) * @min(rx, ry);
if (inner_dist < 1.5) {
const coverage = @max(0, @min(1, 1.5 - inner_dist));
const alpha = @as(u8, @intFromFloat(@as(f32, @floatFromInt(color.a)) * coverage));
blendPixel(fb, x, y, Style.Color.rgba(color.r, color.g, color.b, alpha));
}
}
}
}
}
/// Draw an anti-aliased polygon outline
pub fn drawPolygonAA(
fb: *Framebuffer,
points: []const [2]i32,
color: Style.Color,
thickness: f32,
closed: bool,
) void {
if (points.len < 2) return;
// Draw edges
var i: usize = 0;
while (i < points.len - 1) : (i += 1) {
drawLineAA(fb, points[i][0], points[i][1], points[i + 1][0], points[i + 1][1], color, thickness);
}
// Close the polygon
if (closed and points.len > 2) {
drawLineAA(fb, points[points.len - 1][0], points[points.len - 1][1], points[0][0], points[0][1], color, thickness);
}
}
// =============================================================================
// Helper functions
// =============================================================================
/// Fractional part of a number
fn fpart(x: f32) f32 {
return x - @floor(x);
}
/// Reverse fractional part
fn rfpart(x: f32) f32 {
return 1 - fpart(x);
}
/// Plot a pixel with anti-aliasing coverage
fn plotAA(fb: *Framebuffer, x: i32, y: i32, color: Style.Color, coverage: f32, thickness: f32) void {
const alpha = @as(u8, @intFromFloat(@as(f32, @floatFromInt(color.a)) * @min(1, coverage * thickness)));
blendPixel(fb, x, y, Style.Color.rgba(color.r, color.g, color.b, alpha));
}
/// Blend a pixel with alpha
fn blendPixel(fb: *Framebuffer, x: i32, y: i32, color: Style.Color) void {
if (color.a == 0) return;
if (color.a == 255) {
fb.setPixel(x, y, color);
return;
}
// Get existing pixel
if (fb.getPixel(x, y)) |existing| {
// Unpack existing color
const bg_r: u8 = @truncate(existing >> 24);
const bg_g: u8 = @truncate(existing >> 16);
const bg_b: u8 = @truncate(existing >> 8);
const bg_a: u8 = @truncate(existing);
// Alpha blend
const src_a = @as(u16, color.a);
const dst_a = @as(u16, bg_a);
const inv_a = 255 - src_a;
const out_a = src_a + @divTrunc(dst_a * inv_a, 255);
if (out_a == 0) return;
const out_r = @as(u8, @intCast(@divTrunc(@as(u16, color.r) * src_a + @as(u16, bg_r) * @divTrunc(dst_a * inv_a, 255), out_a)));
const out_g = @as(u8, @intCast(@divTrunc(@as(u16, color.g) * src_a + @as(u16, bg_g) * @divTrunc(dst_a * inv_a, 255), out_a)));
const out_b = @as(u8, @intCast(@divTrunc(@as(u16, color.b) * src_a + @as(u16, bg_b) * @divTrunc(dst_a * inv_a, 255), out_a)));
fb.setPixel(x, y, Style.Color.rgba(out_r, out_g, out_b, @as(u8, @intCast(out_a))));
} else {
fb.setPixel(x, y, color);
}
}
// =============================================================================
// Tests
// =============================================================================
test "fpart and rfpart" {
try std.testing.expectApproxEqAbs(@as(f32, 0.5), fpart(1.5), 0.001);
try std.testing.expectApproxEqAbs(@as(f32, 0.5), rfpart(1.5), 0.001);
try std.testing.expectApproxEqAbs(@as(f32, 0.25), fpart(2.25), 0.001);
try std.testing.expectApproxEqAbs(@as(f32, 0.75), rfpart(2.25), 0.001);
}
test "Quality samples" {
try std.testing.expectEqual(@as(u8, 1), Quality.none.samples());
try std.testing.expectEqual(@as(u8, 2), Quality.low.samples());
try std.testing.expectEqual(@as(u8, 4), Quality.medium.samples());
try std.testing.expectEqual(@as(u8, 8), Quality.high.samples());
try std.testing.expectEqual(@as(u8, 16), Quality.ultra.samples());
}

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//! Visual Effects
//!
//! Provides visual effects like shadows, gradients, and blur.
//! These can be applied to rendered content.
const std = @import("std");
const Framebuffer = @import("framebuffer.zig").Framebuffer;
const Style = @import("../core/style.zig");
const Layout = @import("../core/layout.zig");
/// Gradient direction
pub const GradientDirection = enum {
horizontal, // Left to right
vertical, // Top to bottom
diagonal_down, // Top-left to bottom-right
diagonal_up, // Bottom-left to top-right
radial, // Center outward
};
/// Shadow effect configuration
pub const Shadow = struct {
/// Horizontal offset (positive = right)
offset_x: i32 = 4,
/// Vertical offset (positive = down)
offset_y: i32 = 4,
/// Blur radius (0 = hard shadow)
blur_radius: u8 = 4,
/// Shadow color
color: Style.Color = Style.Color.rgba(0, 0, 0, 128),
/// Spread (makes shadow larger/smaller than element)
spread: i32 = 0,
/// Create a simple drop shadow
pub fn drop(offset: i32, blur: u8) Shadow {
return .{
.offset_x = offset,
.offset_y = offset,
.blur_radius = blur,
};
}
/// Create a soft shadow
pub fn soft() Shadow {
return .{
.offset_x = 0,
.offset_y = 2,
.blur_radius = 8,
.color = Style.Color.rgba(0, 0, 0, 64),
};
}
/// Create a hard shadow
pub fn hard() Shadow {
return .{
.offset_x = 2,
.offset_y = 2,
.blur_radius = 0,
.color = Style.Color.rgba(0, 0, 0, 100),
};
}
};
/// Gradient effect configuration
pub const Gradient = struct {
/// Start color
start_color: Style.Color,
/// End color
end_color: Style.Color,
/// Direction
direction: GradientDirection = .vertical,
/// Optional middle color for 3-stop gradient
middle_color: ?Style.Color = null,
/// Middle position (0.0 - 1.0)
middle_pos: f32 = 0.5,
/// Create a horizontal gradient
pub fn horizontal(start: Style.Color, end: Style.Color) Gradient {
return .{
.start_color = start,
.end_color = end,
.direction = .horizontal,
};
}
/// Create a vertical gradient
pub fn vertical(start: Style.Color, end: Style.Color) Gradient {
return .{
.start_color = start,
.end_color = end,
.direction = .vertical,
};
}
/// Create a diagonal gradient
pub fn diagonal(start: Style.Color, end: Style.Color) Gradient {
return .{
.start_color = start,
.end_color = end,
.direction = .diagonal_down,
};
}
};
/// Apply a shadow to a rectangle
pub fn applyShadow(fb: *Framebuffer, rect: Layout.Rect, shadow: Shadow) void {
if (rect.isEmpty()) return;
// Calculate shadow bounds
const shadow_x = rect.x + shadow.offset_x - shadow.spread;
const shadow_y = rect.y + shadow.offset_y - shadow.spread;
const shadow_w = rect.w +| @as(u32, @intCast(@abs(shadow.spread) * 2));
const shadow_h = rect.h +| @as(u32, @intCast(@abs(shadow.spread) * 2));
if (shadow.blur_radius == 0) {
// Hard shadow - simple filled rect
fb.fillRect(shadow_x, shadow_y, shadow_w, shadow_h, shadow.color);
} else {
// Soft shadow with blur approximation
// Draw multiple layers with decreasing alpha
const layers = @as(u32, @intCast(shadow.blur_radius));
const base_alpha = shadow.color.a;
var layer: u32 = 0;
while (layer <= layers) : (layer += 1) {
const t = @as(f32, @floatFromInt(layer)) / @as(f32, @floatFromInt(layers + 1));
const alpha = @as(u8, @intFromFloat(@as(f32, @floatFromInt(base_alpha)) * (1.0 - t * t)));
const expand = @as(i32, @intCast(layer));
const layer_color = Style.Color.rgba(shadow.color.r, shadow.color.g, shadow.color.b, alpha);
fb.fillRect(
shadow_x - expand,
shadow_y - expand,
shadow_w +| @as(u32, @intCast(expand * 2)),
shadow_h +| @as(u32, @intCast(expand * 2)),
layer_color,
);
}
}
}
/// Apply a gradient fill to a rectangle
pub fn applyGradient(fb: *Framebuffer, rect: Layout.Rect, gradient: Gradient) void {
if (rect.isEmpty()) return;
switch (gradient.direction) {
.horizontal => applyHorizontalGradient(fb, rect, gradient),
.vertical => applyVerticalGradient(fb, rect, gradient),
.diagonal_down => applyDiagonalGradient(fb, rect, gradient, true),
.diagonal_up => applyDiagonalGradient(fb, rect, gradient, false),
.radial => applyRadialGradient(fb, rect, gradient),
}
}
fn applyHorizontalGradient(fb: *Framebuffer, rect: Layout.Rect, gradient: Gradient) void {
var x: u32 = 0;
while (x < rect.w) : (x += 1) {
const t = @as(f32, @floatFromInt(x)) / @as(f32, @floatFromInt(rect.w - 1));
const color = interpolateColor(gradient.start_color, gradient.end_color, t);
fb.fillRect(rect.x + @as(i32, @intCast(x)), rect.y, 1, rect.h, color);
}
}
fn applyVerticalGradient(fb: *Framebuffer, rect: Layout.Rect, gradient: Gradient) void {
var y: u32 = 0;
while (y < rect.h) : (y += 1) {
const t = @as(f32, @floatFromInt(y)) / @as(f32, @floatFromInt(rect.h - 1));
const color = interpolateColor(gradient.start_color, gradient.end_color, t);
fb.fillRect(rect.x, rect.y + @as(i32, @intCast(y)), rect.w, 1, color);
}
}
fn applyDiagonalGradient(fb: *Framebuffer, rect: Layout.Rect, gradient: Gradient, down: bool) void {
const max_dist = @as(f32, @floatFromInt(rect.w + rect.h - 2));
var y: u32 = 0;
while (y < rect.h) : (y += 1) {
var x: u32 = 0;
while (x < rect.w) : (x += 1) {
const dist: f32 = if (down)
@as(f32, @floatFromInt(x + y))
else
@as(f32, @floatFromInt(x + (rect.h - 1 - y)));
const t = dist / max_dist;
const color = interpolateColor(gradient.start_color, gradient.end_color, t);
fb.setPixel(
rect.x + @as(i32, @intCast(x)),
rect.y + @as(i32, @intCast(y)),
color,
);
}
}
}
fn applyRadialGradient(fb: *Framebuffer, rect: Layout.Rect, gradient: Gradient) void {
const cx = @as(f32, @floatFromInt(rect.w)) / 2.0;
const cy = @as(f32, @floatFromInt(rect.h)) / 2.0;
const max_dist = @sqrt(cx * cx + cy * cy);
var y: u32 = 0;
while (y < rect.h) : (y += 1) {
var x: u32 = 0;
while (x < rect.w) : (x += 1) {
const dx = @as(f32, @floatFromInt(x)) - cx;
const dy = @as(f32, @floatFromInt(y)) - cy;
const dist = @sqrt(dx * dx + dy * dy);
const t = @min(1.0, dist / max_dist);
const color = interpolateColor(gradient.start_color, gradient.end_color, t);
fb.setPixel(
rect.x + @as(i32, @intCast(x)),
rect.y + @as(i32, @intCast(y)),
color,
);
}
}
}
/// Interpolate between two colors
pub fn interpolateColor(a: Style.Color, b: Style.Color, t: f32) Style.Color {
const t_clamped = @max(0.0, @min(1.0, t));
return Style.Color.rgba(
@intFromFloat(@as(f32, @floatFromInt(a.r)) * (1 - t_clamped) + @as(f32, @floatFromInt(b.r)) * t_clamped),
@intFromFloat(@as(f32, @floatFromInt(a.g)) * (1 - t_clamped) + @as(f32, @floatFromInt(b.g)) * t_clamped),
@intFromFloat(@as(f32, @floatFromInt(a.b)) * (1 - t_clamped) + @as(f32, @floatFromInt(b.b)) * t_clamped),
@intFromFloat(@as(f32, @floatFromInt(a.a)) * (1 - t_clamped) + @as(f32, @floatFromInt(b.a)) * t_clamped),
);
}
/// Apply simple blur to a region (box blur)
pub fn applyBlur(fb: *Framebuffer, rect: Layout.Rect, radius: u8) void {
if (rect.isEmpty() or radius == 0) return;
// Simple box blur - average of surrounding pixels
const r = @as(i32, @intCast(radius));
const kernel_size = @as(u32, @intCast(2 * r + 1));
const divisor = kernel_size * kernel_size;
// Create a temporary copy of the region
var temp_buf: [256 * 256 * 4]u8 = undefined;
const max_pixels = 256 * 256;
if (rect.w * rect.h > max_pixels) return; // Too large
// Copy original pixels
var py: u32 = 0;
while (py < rect.h) : (py += 1) {
var px: u32 = 0;
while (px < rect.w) : (px += 1) {
const src_x = rect.x + @as(i32, @intCast(px));
const src_y = rect.y + @as(i32, @intCast(py));
if (fb.getPixel(src_x, src_y)) |pixel| {
const idx = (py * rect.w + px) * 4;
// Unpack RGBA from u32
temp_buf[idx + 0] = @truncate(pixel >> 24); // R
temp_buf[idx + 1] = @truncate(pixel >> 16); // G
temp_buf[idx + 2] = @truncate(pixel >> 8); // B
temp_buf[idx + 3] = @truncate(pixel); // A
}
}
}
// Apply blur
py = 0;
while (py < rect.h) : (py += 1) {
var px: u32 = 0;
while (px < rect.w) : (px += 1) {
var sum_r: u32 = 0;
var sum_g: u32 = 0;
var sum_b: u32 = 0;
var sum_a: u32 = 0;
var count: u32 = 0;
// Sample kernel
var ky: i32 = -r;
while (ky <= r) : (ky += 1) {
var kx: i32 = -r;
while (kx <= r) : (kx += 1) {
const sx = @as(i32, @intCast(px)) + kx;
const sy = @as(i32, @intCast(py)) + ky;
if (sx >= 0 and sy >= 0 and
sx < @as(i32, @intCast(rect.w)) and
sy < @as(i32, @intCast(rect.h)))
{
const idx = (@as(u32, @intCast(sy)) * rect.w + @as(u32, @intCast(sx))) * 4;
sum_r += temp_buf[idx + 0];
sum_g += temp_buf[idx + 1];
sum_b += temp_buf[idx + 2];
sum_a += temp_buf[idx + 3];
count += 1;
}
}
}
if (count > 0) {
const color = Style.Color.rgba(
@intCast(sum_r / count),
@intCast(sum_g / count),
@intCast(sum_b / count),
@intCast(sum_a / count),
);
fb.setPixel(
rect.x + @as(i32, @intCast(px)),
rect.y + @as(i32, @intCast(py)),
color,
);
}
}
}
_ = divisor;
}
/// Apply opacity to a color
pub fn applyOpacity(color: Style.Color, opacity: f32) Style.Color {
const new_alpha = @as(u8, @intFromFloat(@as(f32, @floatFromInt(color.a)) * @max(0.0, @min(1.0, opacity))));
return Style.Color.rgba(color.r, color.g, color.b, new_alpha);
}
/// Create a highlight color (lighter version)
pub fn highlight(color: Style.Color, amount: u8) Style.Color {
return Style.Color.rgba(
@min(255, @as(u16, color.r) + amount),
@min(255, @as(u16, color.g) + amount),
@min(255, @as(u16, color.b) + amount),
color.a,
);
}
/// Create a lowlight color (darker version)
pub fn lowlight(color: Style.Color, amount: u8) Style.Color {
return Style.Color.rgba(
@as(u8, @intCast(@max(0, @as(i16, color.r) - amount))),
@as(u8, @intCast(@max(0, @as(i16, color.g) - amount))),
@as(u8, @intCast(@max(0, @as(i16, color.b) - amount))),
color.a,
);
}
// =============================================================================
// Tests
// =============================================================================
test "Shadow presets" {
const soft = Shadow.soft();
try std.testing.expectEqual(@as(i32, 0), soft.offset_x);
try std.testing.expectEqual(@as(u8, 8), soft.blur_radius);
const hard = Shadow.hard();
try std.testing.expectEqual(@as(u8, 0), hard.blur_radius);
}
test "Gradient creation" {
const white = Style.Color.rgba(255, 255, 255, 255);
const black = Style.Color.rgba(0, 0, 0, 255);
const h_grad = Gradient.horizontal(white, black);
try std.testing.expectEqual(GradientDirection.horizontal, h_grad.direction);
const v_grad = Gradient.vertical(white, black);
try std.testing.expectEqual(GradientDirection.vertical, v_grad.direction);
}
test "interpolateColor" {
const white = Style.Color.rgba(255, 255, 255, 255);
const black = Style.Color.rgba(0, 0, 0, 255);
const mid = interpolateColor(black, white, 0.5);
try std.testing.expect(mid.r > 120 and mid.r < 130);
try std.testing.expect(mid.g > 120 and mid.g < 130);
}
test "applyOpacity" {
const color = Style.Color.rgba(255, 0, 0, 255);
const half = applyOpacity(color, 0.5);
try std.testing.expect(half.a > 125 and half.a < 130);
}
test "highlight and lowlight" {
const color = Style.Color.rgba(100, 100, 100, 255);
const hi = highlight(color, 50);
try std.testing.expectEqual(@as(u8, 150), hi.r);
const lo = lowlight(color, 50);
try std.testing.expectEqual(@as(u8, 50), lo.r);
}

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//! Virtual Scrolling
//!
//! Efficiently renders large lists by only rendering visible items.
//! Supports variable item heights and smooth scrolling.
const std = @import("std");
const Context = @import("../core/context.zig").Context;
const Layout = @import("../core/layout.zig");
const Style = @import("../core/style.zig");
const Input = @import("../core/input.zig");
/// Maximum cached item heights
const MAX_CACHED_HEIGHTS = 10000;
/// Virtual scroll state
pub const VirtualScrollState = struct {
/// Scroll offset in pixels
scroll_offset: i32 = 0,
/// Total content height
total_height: u32 = 0,
/// First visible item index
first_visible: usize = 0,
/// Last visible item index
last_visible: usize = 0,
/// Number of items
item_count: usize = 0,
/// Cached item heights (for variable height)
item_heights: [MAX_CACHED_HEIGHTS]u16 = [_]u16{0} ** MAX_CACHED_HEIGHTS,
/// Default item height
default_height: u16 = 24,
/// Is dragging scrollbar
dragging_scrollbar: bool = false,
/// Drag start offset
drag_start_y: i32 = 0,
/// Drag start scroll
drag_start_scroll: i32 = 0,
const Self = @This();
/// Initialize state
pub fn init(item_count: usize, default_height: u16) Self {
return .{
.item_count = item_count,
.default_height = default_height,
};
}
/// Set item count
pub fn setItemCount(self: *Self, count: usize) void {
self.item_count = count;
self.recalculateTotalHeight();
}
/// Set height for a specific item
pub fn setItemHeight(self: *Self, index: usize, height: u16) void {
if (index < MAX_CACHED_HEIGHTS) {
self.item_heights[index] = height;
self.recalculateTotalHeight();
}
}
/// Get height for a specific item
pub fn getItemHeight(self: Self, index: usize) u16 {
if (index < MAX_CACHED_HEIGHTS and self.item_heights[index] > 0) {
return self.item_heights[index];
}
return self.default_height;
}
/// Recalculate total content height
pub fn recalculateTotalHeight(self: *Self) void {
var total: u32 = 0;
var i: usize = 0;
while (i < self.item_count) : (i += 1) {
total += self.getItemHeight(i);
}
self.total_height = total;
}
/// Scroll to a specific item
pub fn scrollToItem(self: *Self, index: usize, viewport_height: u32) void {
if (index >= self.item_count) return;
// Calculate item offset
var offset: i32 = 0;
var i: usize = 0;
while (i < index) : (i += 1) {
offset += self.getItemHeight(i);
}
// Center item in viewport
const item_height = self.getItemHeight(index);
const center_offset = offset - @as(i32, @intCast(viewport_height / 2)) + @divTrunc(@as(i32, item_height), 2);
self.scroll_offset = @max(0, center_offset);
}
/// Ensure item is visible
pub fn ensureVisible(self: *Self, index: usize, viewport_height: u32) void {
if (index >= self.item_count) return;
// Calculate item bounds
var item_top: i32 = 0;
var i: usize = 0;
while (i < index) : (i += 1) {
item_top += self.getItemHeight(i);
}
const item_bottom = item_top + @as(i32, self.getItemHeight(index));
// Check if scrolling needed
if (item_top < self.scroll_offset) {
self.scroll_offset = item_top;
} else if (item_bottom > self.scroll_offset + @as(i32, @intCast(viewport_height))) {
self.scroll_offset = item_bottom - @as(i32, @intCast(viewport_height));
}
}
/// Get offset for a specific item
pub fn getItemOffset(self: Self, index: usize) i32 {
var offset: i32 = 0;
var i: usize = 0;
while (i < index and i < self.item_count) : (i += 1) {
offset += self.getItemHeight(i);
}
return offset;
}
};
/// Virtual scroll configuration
pub const VirtualScrollConfig = struct {
/// Show scrollbar
show_scrollbar: bool = true,
/// Scrollbar width
scrollbar_width: u16 = 12,
/// Overscan (render extra items above/below viewport)
overscan: u16 = 2,
/// Enable smooth scrolling
smooth_scroll: bool = true,
/// Scroll speed (pixels per wheel tick)
scroll_speed: u16 = 48,
/// Minimum thumb size
min_thumb_size: u16 = 20,
};
/// Virtual scroll colors
pub const VirtualScrollColors = struct {
background: Style.Color = Style.Color.rgba(30, 30, 30, 255),
scrollbar_track: Style.Color = Style.Color.rgba(50, 50, 50, 255),
scrollbar_thumb: Style.Color = Style.Color.rgba(100, 100, 100, 255),
scrollbar_thumb_hover: Style.Color = Style.Color.rgba(130, 130, 130, 255),
scrollbar_thumb_active: Style.Color = Style.Color.rgba(160, 160, 160, 255),
};
/// Result from virtual scroll widget
pub const VirtualScrollResult = struct {
/// First visible item index
first_visible: usize,
/// Last visible item index (exclusive)
last_visible: usize,
/// Content area rect (excluding scrollbar)
content_rect: Layout.Rect,
/// Did scroll position change
scrolled: bool,
/// Is scrollbar being dragged
dragging: bool,
};
/// Item callback for rendering
pub const ItemRenderer = *const fn (
ctx: *Context,
index: usize,
rect: Layout.Rect,
user_data: ?*anyopaque,
) void;
/// Render a virtual scroll area
pub fn virtualScroll(
ctx: *Context,
state: *VirtualScrollState,
rect: Layout.Rect,
) VirtualScrollResult {
return virtualScrollEx(ctx, state, rect, .{}, .{});
}
/// Render a virtual scroll area with configuration
pub fn virtualScrollEx(
ctx: *Context,
state: *VirtualScrollState,
rect: Layout.Rect,
config: VirtualScrollConfig,
colors: VirtualScrollColors,
) VirtualScrollResult {
if (rect.isEmpty()) {
return .{
.first_visible = 0,
.last_visible = 0,
.content_rect = rect,
.scrolled = false,
.dragging = false,
};
}
const scrollbar_width: u32 = if (config.show_scrollbar and state.total_height > rect.h)
@as(u32, config.scrollbar_width)
else
0;
const content_rect = Layout.Rect{
.x = rect.x,
.y = rect.y,
.w = rect.w -| scrollbar_width,
.h = rect.h,
};
// Draw background
ctx.pushCommand(.{ .fill_rect = .{
.rect = rect,
.color = colors.background,
} });
// Handle input
var scrolled = false;
const input = ctx.getInput();
// Mouse wheel scrolling
if (rect.contains(input.mouse_x, input.mouse_y)) {
if (input.scroll_y != 0) {
const scroll_delta = -input.scroll_y * @as(i32, config.scroll_speed);
const old_offset = state.scroll_offset;
state.scroll_offset = @max(0, @min(
@as(i32, @intCast(state.total_height)) - @as(i32, @intCast(rect.h)),
state.scroll_offset + scroll_delta,
));
scrolled = old_offset != state.scroll_offset;
}
}
// Scrollbar handling
var dragging = state.dragging_scrollbar;
if (scrollbar_width > 0) {
const scrollbar_rect = Layout.Rect{
.x = rect.x + @as(i32, @intCast(rect.w - scrollbar_width)),
.y = rect.y,
.w = scrollbar_width,
.h = rect.h,
};
// Draw scrollbar track
ctx.pushCommand(.{ .fill_rect = .{
.rect = scrollbar_rect,
.color = colors.scrollbar_track,
} });
// Calculate thumb
if (state.total_height > rect.h) {
const visible_ratio = @as(f32, @floatFromInt(rect.h)) / @as(f32, @floatFromInt(state.total_height));
const thumb_height = @max(
config.min_thumb_size,
@as(u32, @intFromFloat(visible_ratio * @as(f32, @floatFromInt(rect.h)))),
);
const scroll_range = state.total_height - rect.h;
const thumb_range = rect.h - thumb_height;
const thumb_pos = if (scroll_range > 0)
@as(u32, @intFromFloat(
@as(f32, @floatFromInt(state.scroll_offset)) /
@as(f32, @floatFromInt(scroll_range)) *
@as(f32, @floatFromInt(thumb_range)),
))
else
0;
const thumb_rect = Layout.Rect{
.x = scrollbar_rect.x + 2,
.y = scrollbar_rect.y + @as(i32, @intCast(thumb_pos)),
.w = scrollbar_width - 4,
.h = thumb_height,
};
// Handle scrollbar dragging
const thumb_hovered = thumb_rect.contains(input.mouse_x, input.mouse_y);
if (state.dragging_scrollbar) {
if (input.mouse_down) {
const delta = input.mouse_y - state.drag_start_y;
const scroll_delta = if (thumb_range > 0)
@as(i32, @intFromFloat(
@as(f32, @floatFromInt(delta)) /
@as(f32, @floatFromInt(thumb_range)) *
@as(f32, @floatFromInt(scroll_range)),
))
else
0;
const old_offset = state.scroll_offset;
state.scroll_offset = @max(0, @min(
@as(i32, @intCast(scroll_range)),
state.drag_start_scroll + scroll_delta,
));
scrolled = old_offset != state.scroll_offset;
} else {
state.dragging_scrollbar = false;
dragging = false;
}
} else if (thumb_hovered and input.mouse_pressed) {
state.dragging_scrollbar = true;
state.drag_start_y = input.mouse_y;
state.drag_start_scroll = state.scroll_offset;
dragging = true;
}
// Draw thumb
const thumb_color = if (state.dragging_scrollbar)
colors.scrollbar_thumb_active
else if (thumb_hovered)
colors.scrollbar_thumb_hover
else
colors.scrollbar_thumb;
ctx.pushCommand(.{ .fill_rect = .{
.rect = thumb_rect,
.color = thumb_color,
} });
}
}
// Calculate visible range
const viewport_height = rect.h;
var first_visible: usize = 0;
var last_visible: usize = 0;
var accumulated_height: i32 = 0;
// Find first visible
var i: usize = 0;
while (i < state.item_count) : (i += 1) {
const item_height = state.getItemHeight(i);
if (accumulated_height + @as(i32, item_height) > state.scroll_offset) {
first_visible = i;
break;
}
accumulated_height += item_height;
}
// Apply overscan
if (first_visible > config.overscan) {
first_visible -= config.overscan;
} else {
first_visible = 0;
}
// Find last visible
accumulated_height = 0;
i = 0;
while (i < first_visible) : (i += 1) {
accumulated_height += state.getItemHeight(i);
}
i = first_visible;
while (i < state.item_count) : (i += 1) {
if (accumulated_height > state.scroll_offset + @as(i32, @intCast(viewport_height))) {
break;
}
accumulated_height += state.getItemHeight(i);
last_visible = i + 1;
}
// Apply overscan
last_visible = @min(state.item_count, last_visible + config.overscan);
// Update state
state.first_visible = first_visible;
state.last_visible = last_visible;
return .{
.first_visible = first_visible,
.last_visible = last_visible,
.content_rect = content_rect,
.scrolled = scrolled,
.dragging = dragging,
};
}
/// Get the rect for a specific item
pub fn getItemRect(
state: *const VirtualScrollState,
content_rect: Layout.Rect,
index: usize,
) Layout.Rect {
if (index >= state.item_count) {
return Layout.Rect{ .x = 0, .y = 0, .w = 0, .h = 0 };
}
const item_offset = state.getItemOffset(index);
const item_height = state.getItemHeight(index);
return Layout.Rect{
.x = content_rect.x,
.y = content_rect.y + item_offset - state.scroll_offset,
.w = content_rect.w,
.h = item_height,
};
}
/// Render visible items using a callback
pub fn renderItems(
ctx: *Context,
state: *const VirtualScrollState,
result: VirtualScrollResult,
renderer: ItemRenderer,
user_data: ?*anyopaque,
) void {
var i: usize = result.first_visible;
while (i < result.last_visible) : (i += 1) {
const item_rect = getItemRect(state, result.content_rect, i);
renderer(ctx, i, item_rect, user_data);
}
}
// =============================================================================
// Tests
// =============================================================================
test "VirtualScrollState init" {
const state = VirtualScrollState.init(100, 24);
try std.testing.expectEqual(@as(usize, 100), state.item_count);
try std.testing.expectEqual(@as(u16, 24), state.default_height);
}
test "VirtualScrollState item heights" {
var state = VirtualScrollState.init(10, 24);
// Default height
try std.testing.expectEqual(@as(u16, 24), state.getItemHeight(0));
// Custom height
state.setItemHeight(5, 48);
try std.testing.expectEqual(@as(u16, 48), state.getItemHeight(5));
}
test "VirtualScrollState total height" {
var state = VirtualScrollState.init(10, 20);
state.recalculateTotalHeight();
// 10 items * 20 pixels = 200
try std.testing.expectEqual(@as(u32, 200), state.total_height);
// Set custom height
state.setItemHeight(0, 40); // 40 instead of 20
try std.testing.expectEqual(@as(u32, 220), state.total_height);
}
test "VirtualScrollState item offset" {
var state = VirtualScrollState.init(5, 30);
state.recalculateTotalHeight();
try std.testing.expectEqual(@as(i32, 0), state.getItemOffset(0));
try std.testing.expectEqual(@as(i32, 30), state.getItemOffset(1));
try std.testing.expectEqual(@as(i32, 60), state.getItemOffset(2));
try std.testing.expectEqual(@as(i32, 120), state.getItemOffset(4));
}
test "VirtualScrollState ensure visible" {
var state = VirtualScrollState.init(100, 20);
state.recalculateTotalHeight();
// Item at position 50*20 = 1000
state.ensureVisible(50, 200);
// Should scroll so item 50 is visible
try std.testing.expect(state.scroll_offset >= 800);
try std.testing.expect(state.scroll_offset <= 1000);
}
test "getItemRect" {
var state = VirtualScrollState.init(10, 30);
state.scroll_offset = 0;
const content_rect = Layout.Rect{ .x = 0, .y = 0, .w = 200, .h = 100 };
const rect0 = getItemRect(&state, content_rect, 0);
try std.testing.expectEqual(@as(i32, 0), rect0.y);
try std.testing.expectEqual(@as(u32, 30), rect0.h);
const rect2 = getItemRect(&state, content_rect, 2);
try std.testing.expectEqual(@as(i32, 60), rect2.y);
}
test "getItemRect with scroll offset" {
var state = VirtualScrollState.init(10, 30);
state.scroll_offset = 45; // Scroll past 1.5 items
const content_rect = Layout.Rect{ .x = 0, .y = 0, .w = 200, .h = 100 };
const rect0 = getItemRect(&state, content_rect, 0);
try std.testing.expectEqual(@as(i32, -45), rect0.y);
const rect2 = getItemRect(&state, content_rect, 2);
try std.testing.expectEqual(@as(i32, 15), rect2.y); // 60 - 45
}

View file

@ -41,6 +41,7 @@ pub const breadcrumb = @import("breadcrumb.zig");
pub const canvas = @import("canvas.zig");
pub const chart = @import("chart.zig");
pub const icon = @import("icon.zig");
pub const virtual_scroll = @import("virtual_scroll.zig");
// =============================================================================
// Re-exports for convenience
@ -313,6 +314,13 @@ pub const IconSize = icon.Size;
pub const IconConfig = icon.Config;
pub const IconColors = icon.Colors;
// VirtualScroll
pub const VirtualScroll = virtual_scroll;
pub const VirtualScrollState = virtual_scroll.VirtualScrollState;
pub const VirtualScrollConfig = virtual_scroll.VirtualScrollConfig;
pub const VirtualScrollColors = virtual_scroll.VirtualScrollColors;
pub const VirtualScrollResult = virtual_scroll.VirtualScrollResult;
// =============================================================================
// Tests
// =============================================================================

View file

@ -69,8 +69,38 @@ pub const render = struct {
pub const ttf = @import("render/ttf.zig");
pub const TtfFont = ttf.TtfFont;
pub const FontRef = ttf.FontRef;
pub const animation = @import("render/animation.zig");
pub const effects = @import("render/effects.zig");
pub const antialiasing = @import("render/antialiasing.zig");
};
// Animation re-exports
pub const Animation = render.animation.Animation;
pub const AnimationManager = render.animation.AnimationManager;
pub const Easing = render.animation.Easing;
pub const lerp = render.animation.lerp;
pub const lerpInt = render.animation.lerpInt;
// Effects re-exports
pub const Shadow = render.effects.Shadow;
pub const Gradient = render.effects.Gradient;
pub const GradientDirection = render.effects.GradientDirection;
pub const applyShadow = render.effects.applyShadow;
pub const applyGradient = render.effects.applyGradient;
pub const applyBlur = render.effects.applyBlur;
pub const interpolateColor = render.effects.interpolateColor;
pub const applyOpacity = render.effects.applyOpacity;
pub const highlight = render.effects.highlight;
pub const lowlight = render.effects.lowlight;
// Anti-aliasing re-exports
pub const AAQuality = render.antialiasing.Quality;
pub const drawLineAA = render.antialiasing.drawLineAA;
pub const drawCircleAA = render.antialiasing.drawCircleAA;
pub const drawRoundedRectAA = render.antialiasing.drawRoundedRectAA;
pub const drawEllipseAA = render.antialiasing.drawEllipseAA;
pub const drawPolygonAA = render.antialiasing.drawPolygonAA;
// =============================================================================
// Backend
// =============================================================================