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const std = @import("std");
pub const Pixel = packed struct(u32) {
blue: u8,
green: u8,
red: u8,
_padding: u8 = 0x0,
};
pub const Canvas = struct {
const Self = @This();
width: u32,
height: u32,
buffer: []volatile Pixel,
pub fn fill(self: *const Canvas, pixel: Pixel) void {
@memset(self.buffer, pixel);
}
fn gaussian_mean(values: [9]u32) u32 {
return (values[0] + values[1] * 2 + values[2] +
values[3] * 2 + values[4] * 8 + values[5] * 2 +
values[6] + values[7] * 2 + values[8]) / 20;
}
pub fn set_with_anti_aliasing(self: *const Canvas, x: u32, y: u32) void {
var neighbors_red: [9]u32 = undefined;
var neighbors_green: [9]u32 = undefined;
var neighbors_blue: [9]u32 = undefined;
for (0..3) |h| {
for (0..3) |w| {
const pixel = self.buffer[(y + 1 - h) * self.width + x + 1 - w];
neighbors_red[w + 3 * h] = pixel.red;
neighbors_green[w + 3 * h] = pixel.green;
neighbors_blue[w + 3 * h] = pixel.blue;
}
}
self.buffer[x + (y * self.width)] = .{
.red = @intCast(Self.gaussian_mean(neighbors_red)),
.green = @intCast(Self.gaussian_mean(neighbors_green)),
.blue = @intCast(Self.gaussian_mean(neighbors_blue)),
};
}
};
pub const Box = struct {
const Self = @This();
x: u32,
y: u32,
width: u32,
height: u32,
color: Pixel,
radius: u32 = 0,
fn render_rect(
self: *const Self,
x: u32,
y: u32,
width: u32,
height: u32,
canvas: *const Canvas
) void {
if (x >= canvas.width or y >= canvas.height) {
return;
}
const x_end = @min(x + width, canvas.width);
const y_end = @min(y + height, canvas.height);
for (y..y_end) |yp| {
const offset = yp * canvas.width;
@memset(
canvas.buffer[(offset + x)..(offset + x_end)],
self.color
);
}
}
pub fn render(self: *const Self, canvas: *const Canvas) void {
if (self.radius == 0) {
self.render_rect(self.x, self.y, self.width, self.height, canvas);
return;
}
const radius = @min(self.radius, self.width / 2, self.height / 2);
const core_width = self.width - 2 * radius;
const core_height = self.height - 2 * radius;
self.render_rect(
self.x + radius,
self.y,
core_width,
radius,
canvas
);
self.render_rect(
self.x + radius,
self.y + radius + core_height,
core_width,
radius,
canvas
);
self.render_rect(
self.x,
self.y + radius,
self.width,
core_height,
canvas
);
for (0..radius) |yp| {
const width: u32 = @intFromFloat(std.math.round(
@as(f64, @floatFromInt(radius)) *
@cos(std.math.asin(
@as(f64, @floatFromInt(yp)) / @as(f64, @floatFromInt(radius))
))
));
const spacing = radius - width;
var offset = ((radius - yp) + self.y) * canvas.width + self.x + spacing;
@memset(
canvas.buffer[offset..offset + width],
self.color
);
offset = ((radius - yp) + self.y) * canvas.width + self.x + core_width + radius;
@memset(
canvas.buffer[offset..offset + width],
self.color
);
offset = (yp + self.y + radius + core_height) * canvas.width + self.x + spacing;
@memset(
canvas.buffer[offset..offset + width],
self.color
);
offset = (yp + self.y + radius + core_height) * canvas.width + self.x + core_width + radius;
@memset(
canvas.buffer[offset..offset + width],
self.color
);
}
for (0..radius) |yp| {
const width: u32 = @intFromFloat(std.math.round(
@as(f64, @floatFromInt(radius)) *
@cos(std.math.asin(
@as(f64, @floatFromInt(yp)) / @as(f64, @floatFromInt(radius))
))
));
const spacing = radius - width;
canvas.set_with_anti_aliasing(
self.x + spacing,
@intCast(self.y + radius - yp),
);
canvas.set_with_anti_aliasing(
self.x + spacing - 1,
@intCast(self.y + radius - yp),
);
canvas.set_with_anti_aliasing(
self.x + core_width + radius + width,
@intCast(self.y + radius - yp),
);
canvas.set_with_anti_aliasing(
self.x + spacing,
@intCast(self.y + yp + radius + core_height),
);
canvas.set_with_anti_aliasing(
self.x + core_width + radius + width,
@intCast(self.y + yp + radius + core_height),
);
}
for (0..core_width) |w| {
canvas.set_with_anti_aliasing(@intCast(self.x + radius + w), self.y);
canvas.set_with_anti_aliasing(@intCast(self.x + radius + w), self.y + self.height);
}
for (0..core_height) |h| {
canvas.set_with_anti_aliasing(self.x, @intCast(self.y + radius + h));
canvas.set_with_anti_aliasing(self.x + self.width, @intCast(self.y + radius + h));
}
}
};
|
