graphics: add line

6 files changed, 254 insertions, 197 deletions

diff --git a/src/estd/graphics/box.zig b/src/estd/graphics/box.zig
new file mode 100644
index 0000000..83868aa
--- /dev/null
+++ b/src/estd/graphics/box.zig
@@ -0,0 +1,101 @@
+const std = @import("std");
+const graphics = @import("root.zig");
+
+pub const Box = struct {
+	const Self = @This();
+
+	x: u32,
+	y: u32,
+	width: u32,
+	height: u32,
+	color: graphics.Color,
+	radius: u32 = 0,
+
+	fn render_rect(
+		self: *const Self,
+		x: u32,
+		y: u32,
+		width: u32,
+		height: u32,
+		canvas: *const graphics.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 graphics.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(@round(std.math.sqrt(@as(f64, @floatFromInt(radius * radius - yp * yp)))));
+			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
+			);
+		}
+	}
+};
diff --git a/src/estd/graphics/canvas.zig b/src/estd/graphics/canvas.zig
new file mode 100644
index 0000000..35dba4b
--- /dev/null
+++ b/src/estd/graphics/canvas.zig
@@ -0,0 +1,13 @@
+const graphics = @import("root.zig");
+
+pub const Canvas = struct {
+	const Self = @This();
+
+	width: u32,
+	height: u32,
+	buffer: []volatile graphics.Color,
+
+	pub fn fill(self: *const Canvas, color: graphics.Color) void {
+		@memset(self.buffer, color);
+	}
+};
diff --git a/src/estd/graphics/color.zig b/src/estd/graphics/color.zig
new file mode 100644
index 0000000..b7fd97e
--- /dev/null
+++ b/src/estd/graphics/color.zig
@@ -0,0 +1,23 @@
+pub const Color = packed struct(u32) {
+	const Self = @This();
+
+	blue: u8,
+	green: u8,
+	red: u8,
+	_padding: u8 = 0x0,
+
+	pub fn mix(self: *const Self, other: *const Self, factor: f64) Self {
+		const inverse = 1 - factor;
+		return Self {
+			.red = @intFromFloat(
+				@as(f64, @floatFromInt(self.red)) * inverse + @as(f64, @floatFromInt(other.red)) * factor
+			),
+			.green = @intFromFloat(
+				@as(f64, @floatFromInt(self.green)) * inverse + @as(f64, @floatFromInt(other.green)) * factor
+			),
+			.blue = @intFromFloat(
+				@as(f64, @floatFromInt(self.blue)) * inverse + @as(f64, @floatFromInt(other.blue)) * factor
+			),
+		};
+	}
+};
diff --git a/src/estd/graphics/curve.zig b/src/estd/graphics/curve.zig
new file mode 100644
index 0000000..d4be1d7
--- /dev/null
+++ b/src/estd/graphics/curve.zig
@@ -0,0 +1,36 @@
+const std = @import("std");
+const graphics = @import("root.zig");
+
+pub const Curve = struct {
+	const Self = @This();
+	const Point = struct {
+		x: u32,
+		y: u32,
+	};
+
+	start: Point,
+	middle: Point,
+	end: Point,
+
+	color: graphics.Color,
+
+	pub fn render(self: *const Self, canvas: *const graphics.Canvas) void {
+		const start_x: f64 = @floatFromInt(self.start.x);
+		const start_y: f64 = @floatFromInt(self.start.y);
+		const middle_x: f64 = @floatFromInt(self.middle.x);
+		const middle_y: f64 = @floatFromInt(self.middle.y);
+		const end_x: f64 = @floatFromInt(self.end.x);
+		const end_y: f64 = @floatFromInt(self.end.y);
+
+		for (0..100) |index| {
+			const t: f64 = @as(f64, @floatFromInt(index)) / 100;
+			const x: u32 = @intFromFloat(@round(
+				(1 - t) * ((1 - t) * start_x + t * middle_x) + t * ((1 - t) * middle_x + t * end_x)
+			));
+			const y: u32 = @intFromFloat(@round(
+				(1 - t) * ((1 - t) * start_y + t * middle_y) + t * ((1 - t) * middle_y + t * end_y)
+			));
+			canvas.buffer[x + canvas.width * y] = self.color;
+		}
+	}
+};
diff --git a/src/estd/graphics/line.zig b/src/estd/graphics/line.zig
new file mode 100644
index 0000000..93f17ff
--- /dev/null
+++ b/src/estd/graphics/line.zig
@@ -0,0 +1,76 @@
+const std = @import("std");
+const graphics = @import("root.zig");
+
+pub const Line = struct {
+	const Self = @This();
+	const Point = struct {
+		x: u32,
+		y: u32,
+	};
+
+	start: Point,
+	end: Point,
+
+	color: graphics.Color,
+
+	fn distance(a: u32, b: u32) u32 {
+		if (a < b) {
+			return b - a;
+		} else {
+			return a - b;
+		}
+	}
+
+	pub fn render(self: *const Self, canvas: *const graphics.Canvas) void {
+		var start = self.start;
+		var end = self.end;
+		const steep = distance(start.y, end.y) > distance(start.x, end.x);
+
+		if (steep) {
+			std.mem.swap(u32, &start.x, &start.y);
+			std.mem.swap(u32, &end.x, &end.y);
+		}
+
+		if (start.x > end.x) {
+			std.mem.swap(Point, &start, &end);
+		}
+
+		const dx: f64 = @floatFromInt(end.x - start.x);
+		const dy: f64 = @floatFromInt(@as(i64, @intCast(end.y)) - @as(i64, @intCast(start.y)));
+		var gradient: f64 = dy / dx;
+		if  (dx == 0) {
+			gradient = 1;
+		}
+
+
+		var intersect_y: f64 = @floatFromInt(start.y);
+
+		if (steep) {
+			for (start.x..end.x + 1) |x| {
+				const y: usize = @intFromFloat(intersect_y);
+				const factor = intersect_y - @as(f64, @floatFromInt(y));
+
+				var previous_color = canvas.buffer[canvas.width * x + y];
+				canvas.buffer[x * canvas.width + y] = previous_color.mix(&self.color, factor);
+
+				previous_color = canvas.buffer[x * canvas.width + y - 1];
+				canvas.buffer[x * canvas.width + y - 1] = self.color.mix(&previous_color, factor);
+
+				intersect_y += gradient;
+			}
+		} else {
+			for (start.x..end.x + 1) |x| {
+				const y: u32 = @intFromFloat(intersect_y);
+				const factor = intersect_y - @as(f64, @floatFromInt(y));
+
+				var previous_color = canvas.buffer[x + canvas.width * y];
+				canvas.buffer[x + canvas.width * y] = previous_color.mix(&self.color, factor);
+
+				previous_color = canvas.buffer[x + canvas.width * (y - 1)];
+				canvas.buffer[x + canvas.width * (y - 1)] = self.color.mix(&previous_color, factor);
+
+				intersect_y += gradient;
+			}
+		}
+	}
+};
diff --git a/src/estd/graphics/root.zig b/src/estd/graphics/root.zig
index da09450..533d518 100644
--- a/src/estd/graphics/root.zig
+++ b/src/estd/graphics/root.zig
@@ -1,197 +1,5 @@
-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));
-		}
-	}
-};
+pub const Canvas = @import("canvas.zig").Canvas;
+pub const Box = @import("box.zig").Box;
+pub const Color = @import("color.zig").Color;
+pub const Line = @import("line.zig").Line;
+pub const Curve = @import("curve.zig").Curve;