estd: add graphics module

2 files changed, 198 insertions, 0 deletions

diff --git a/src/estd/graphics/root.zig b/src/estd/graphics/root.zig
new file mode 100644
index 0000000..da09450
--- /dev/null
+++ b/src/estd/graphics/root.zig
@@ -0,0 +1,197 @@
+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));
+		}
+	}
+};
diff --git a/src/estd/root.zig b/src/estd/root.zig
index 00c2631..5ff292e 100644
--- a/src/estd/root.zig
+++ b/src/estd/root.zig
@@ -2,6 +2,7 @@ const std = @import("std");
 
 pub const cursor = @import("cursor.zig");
 pub const parser = @import("parser/root.zig");
+pub const graphics = @import("graphics/root.zig");
 
 test {
 	std.testing.refAllDecls(@This());