font/sprite: address PR review feedback

- Make canvas geometry primitives generic, use `Rect(u32)` for `rect`
function, so that we don't have to worry about negatives or rounding.
- Make `Quads` struct packed just in case it gets non-comptime use in
the future.
- Clarify comment on why we're discarding out of range pixels + runtime
unreachable for any other type of error which we shouldn't ever see.
- Move z2d import above in-tree imports.

src/font/sprite/Box.zig

@@ -20,11 +20,11 @@ const std = @import("std");
 const assert = std.debug.assert;
 const Allocator = std.mem.Allocator;
 
+const z2d = @import("z2d");
+
 const font = @import("../main.zig");
 const Sprite = @import("../sprite.zig").Sprite;
 
-const z2d = @import("z2d");
-
 const log = std.log.scoped(.box_font);
 
 /// The cell width and height because the boxes are fit perfectly
@@ -72,7 +72,7 @@ const Lines = packed struct(u8) {
 
 /// Specification of a quadrants char, which has each of the
 /// 4 quadrants of the character cell either filled or empty.
-const Quads = struct {
+const Quads = packed struct(u4) {
     tl: bool = false,
     tr: bool = false,
     bl: bool = false,
@@ -1621,10 +1621,10 @@ fn draw_block_shade(
     };
 
     canvas.rect(.{
-        .x = @floatFromInt(x),
-        .y = @floatFromInt(y),
-        .width = @floatFromInt(w),
-        .height = @floatFromInt(h),
+        .x = x,
+        .y = y,
+        .width = w,
+        .height = h,
     }, @as(font.sprite.Color, @enumFromInt(@intFromEnum(shade))));
 }
 
@@ -1671,10 +1671,10 @@ fn draw_checkerboard_fill(self: Box, canvas: *font.sprite.Canvas, parity: u1) vo
             const y1 = (self.height * (y + 1)) / y_size;
             if ((x + y) % 2 == parity) {
                 canvas.rect(.{
-                    .x = @floatFromInt(x0),
-                    .y = @floatFromInt(y0),
-                    .width = @floatFromInt(x1 -| x0),
-                    .height = @floatFromInt(y1 -| y0),
+                    .x = @intCast(x0),
+                    .y = @intCast(y0),
+                    .width = @intCast(x1 -| x0),
+                    .height = @intCast(y1 -| y0),
                 }, .on);
             }
         }
@@ -1841,8 +1841,8 @@ fn draw_circle(
 fn draw_line(
     self: Box,
     canvas: *font.sprite.Canvas,
-    p0: font.sprite.Point,
-    p1: font.sprite.Point,
+    p0: font.sprite.Point(f64),
+    p1: font.sprite.Point(f64),
     comptime thickness: Thickness,
 ) !void {
     canvas.line(
@@ -1853,11 +1853,11 @@ fn draw_line(
 }
 
 fn draw_shade(self: Box, canvas: *font.sprite.Canvas, v: u16) void {
-    canvas.rect((font.sprite.Box{
+    canvas.rect((font.sprite.Box(u32){
         .p0 = .{ .x = 0, .y = 0 },
         .p1 = .{
-            .x = @floatFromInt(self.width),
-            .y = @floatFromInt(self.height),
+            .x = self.width,
+            .y = self.height,
         },
     }).rect(), @as(font.sprite.Color, @enumFromInt(v)));
 }
@@ -2395,12 +2395,12 @@ fn vline(
     x: u32,
     thickness_px: u32,
 ) void {
-    canvas.rect((font.sprite.Box{ .p0 = .{
-        .x = @floatFromInt(@min(@max(x, 0), self.width)),
-        .y = @floatFromInt(@min(@max(y1, 0), self.height)),
+    canvas.rect((font.sprite.Box(u32){ .p0 = .{
+        .x = @min(@max(x, 0), self.width),
+        .y = @min(@max(y1, 0), self.height),
     }, .p1 = .{
-        .x = @floatFromInt(@min(@max(x + thickness_px, 0), self.width)),
-        .y = @floatFromInt(@min(@max(y2, 0), self.height)),
+        .x = @min(@max(x + thickness_px, 0), self.width),
+        .y = @min(@max(y2, 0), self.height),
     } }).rect(), .on);
 }
 
@@ -2412,12 +2412,12 @@ fn hline(
     y: u32,
     thickness_px: u32,
 ) void {
-    canvas.rect((font.sprite.Box{ .p0 = .{
-        .x = @floatFromInt(@min(@max(x1, 0), self.width)),
-        .y = @floatFromInt(@min(@max(y, 0), self.height)),
+    canvas.rect((font.sprite.Box(u32){ .p0 = .{
+        .x = @min(@max(x1, 0), self.width),
+        .y = @min(@max(y, 0), self.height),
     }, .p1 = .{
-        .x = @floatFromInt(@min(@max(x2, 0), self.width)),
-        .y = @floatFromInt(@min(@max(y + thickness_px, 0), self.height)),
+        .x = @min(@max(x2, 0), self.width),
+        .y = @min(@max(y + thickness_px, 0), self.height),
     } }).rect(), .on);
 }
 
@@ -2429,12 +2429,12 @@ fn rect(
     x2: u32,
     y2: u32,
 ) void {
-    canvas.rect((font.sprite.Box{ .p0 = .{
-        .x = @floatFromInt(@min(@max(x1, 0), self.width)),
-        .y = @floatFromInt(@min(@max(y1, 0), self.height)),
+    canvas.rect((font.sprite.Box(u32){ .p0 = .{
+        .x = @min(@max(x1, 0), self.width),
+        .y = @min(@max(y1, 0), self.height),
     }, .p1 = .{
-        .x = @floatFromInt(@min(@max(x2, 0), self.width)),
-        .y = @floatFromInt(@min(@max(y2, 0), self.height)),
+        .x = @min(@max(x2, 0), self.width),
+        .y = @min(@max(y2, 0), self.height),
     } }).rect(), .on);
 }
 

src/font/sprite/Powerline.zig

@@ -391,8 +391,8 @@ fn draw_half_circle(self: Powerline, alloc: Allocator, canvas: *font.sprite.Canv
                 const average = @as(u8, @intCast(@min(total / (supersample * supersample), 0xFF)));
                 canvas.rect(
                     .{
-                        .x = @floatFromInt(c),
-                        .y = @floatFromInt(r),
+                        .x = @intCast(c),
+                        .y = @intCast(r),
                         .width = 1,
                         .height = 1,
                     },
@@ -404,7 +404,7 @@ fn draw_half_circle(self: Powerline, alloc: Allocator, canvas: *font.sprite.Canv
 }
 
 fn draw_trapezoid_top_bottom(self: Powerline, canvas: *font.sprite.Canvas, cp: u32) !void {
-    const t_top: Quad = if (cp == 0xE0D4)
+    const t_top: Quad(f64) = if (cp == 0xE0D4)
         .{
             .p0 = .{
                 .x = 0,
@@ -443,7 +443,7 @@ fn draw_trapezoid_top_bottom(self: Powerline, canvas: *font.sprite.Canvas, cp: u
             },
         };
 
-    const t_bottom: Quad = if (cp == 0xE0D4)
+    const t_bottom: Quad(f64) = if (cp == 0xE0D4)
         .{
             .p0 = .{
                 .x = @floatFromInt(self.width - self.width / 3),

src/font/sprite/canvas.zig

@@ -6,53 +6,66 @@ const Allocator = std.mem.Allocator;
 const z2d = @import("z2d");
 const font = @import("../main.zig");
 
-pub const Point = struct {
-    x: f64,
-    y: f64,
-};
+pub fn Point(comptime T: type) type {
+    return struct {
+        x: T,
+        y: T,
+    };
+}
 
-pub const Line = struct {
-    p0: Point,
-    p1: Point,
-};
+pub fn Line(comptime T: type) type {
+    return struct {
+        p0: Point(T),
+        p1: Point(T),
+    };
+}
 
-pub const Box = struct {
-    p0: Point,
-    p1: Point,
+pub fn Box(comptime T: type) type {
+    return struct {
+        p0: Point(T),
+        p1: Point(T),
 
-    pub fn rect(self: Box) Rect {
-        const tl_x = @min(self.p0.x, self.p1.x);
-        const tl_y = @min(self.p0.y, self.p1.y);
-        const br_x = @max(self.p0.x, self.p1.x);
-        const br_y = @max(self.p0.y, self.p1.y);
-        return .{
-            .x = tl_x,
-            .y = tl_y,
-            .width = br_x - tl_x,
-            .height = br_y - tl_y,
-        };
-    }
-};
+        pub fn rect(self: Box(T)) Rect(T) {
+            const tl_x = @min(self.p0.x, self.p1.x);
+            const tl_y = @min(self.p0.y, self.p1.y);
+            const br_x = @max(self.p0.x, self.p1.x);
+            const br_y = @max(self.p0.y, self.p1.y);
 
-pub const Rect = struct {
-    x: f64,
-    y: f64,
-    width: f64,
-    height: f64,
-};
+            return .{
+                .x = tl_x,
+                .y = tl_y,
+                .width = br_x - tl_x,
+                .height = br_y - tl_y,
+            };
+        }
+    };
+}
 
-pub const Triangle = struct {
-    p0: Point,
-    p1: Point,
-    p2: Point,
-};
+pub fn Rect(comptime T: type) type {
+    return struct {
+        x: T,
+        y: T,
+        width: T,
+        height: T,
+    };
+}
 
-pub const Quad = struct {
-    p0: Point,
-    p1: Point,
-    p2: Point,
-    p3: Point,
-};
+pub fn Triangle(comptime T: type) type {
+    return struct {
+        p0: Point(T),
+        p1: Point(T),
+        p2: Point(T),
+    };
+}
+
+pub fn Quad(comptime T: type) type {
+    return struct {
+        p0: Point(T),
+        p1: Point(T),
+        p2: Point(T),
+        p3: Point(T),
+    };
+}
 
 /// We only use alpha-channel so a pixel can only be "on" or "off".
 pub const Color = enum(u8) {
@@ -137,19 +150,26 @@ pub const Canvas = struct {
             @intCast(x),
             @intCast(y),
             .{ .alpha8 = .{ .a = @intFromEnum(color) } },
-        ) catch {
-            // If we try to set out of range this will fail.
-            // We just silently ignore that.
+        ) catch |e| switch (e) {
+            error.OutOfRange => {
+                // If we try to set out of range this will fail. We just silently
+                // ignore it, so that this method (and `rect` which uses it) have
+                // implicit bounds clipping.
+            },
+            else => {
+                std.log.err("Wtf? err={}", .{e});
+                unreachable; // This shouldn't be possible.
+            },
         };
     }
 
     /// Draw and fill a rectangle. This is the main primitive for drawing
     /// lines as well (which are just generally skinny rectangles...)
-    pub fn rect(self: *Canvas, v: Rect, color: Color) void {
-        const x0: usize = @intFromFloat(v.x);
-        const x1: usize = @intFromFloat(v.x + v.width);
-        const y0: usize = @intFromFloat(v.y);
-        const y1: usize = @intFromFloat(v.y + v.height);
+    pub fn rect(self: *Canvas, v: Rect(u32), color: Color) void {
+        const x0 = v.x;
+        const x1 = v.x + v.width;
+        const y0 = v.y;
+        const y1 = v.y + v.height;
 
         for (y0..y1) |y| {
             for (x0..x1) |x| {
@@ -163,7 +183,7 @@ pub const Canvas = struct {
     }
 
     /// Draw and fill a quad.
-    pub fn quad(self: *Canvas, q: Quad, color: Color) !void {
+    pub fn quad(self: *Canvas, q: Quad(f64), color: Color) !void {
         var ctx: z2d.Context = .{
             .surface = self.sfc,
             .pattern = .{
@@ -186,7 +206,7 @@ pub const Canvas = struct {
     }
 
     /// Draw and fill a triangle.
-    pub fn triangle(self: *Canvas, t: Triangle, color: Color) !void {
+    pub fn triangle(self: *Canvas, t: Triangle(f64), color: Color) !void {
         var ctx: z2d.Context = .{
             .surface = self.sfc,
             .pattern = .{
@@ -208,7 +228,7 @@ pub const Canvas = struct {
     }
 
     /// Stroke a line.
-    pub fn line(self: *Canvas, l: Line, thickness: f64, color: Color) !void {
+    pub fn line(self: *Canvas, l: Line(f64), thickness: f64, color: Color) !void {
         var ctx: z2d.Context = .{
             .surface = self.sfc,
             .pattern = .{

src/font/sprite/underline.zig

@@ -70,8 +70,8 @@ fn drawSingle(alloc: Allocator, width: u32, thickness: u32) !CanvasAndOffset {
     canvas.rect(.{
         .x = 0,
         .y = 0,
-        .width = @floatFromInt(width),
-        .height = @floatFromInt(thickness),
+        .width = width,
+        .height = thickness,
     }, .on);
 
     const offset_y: i32 = 0;
@@ -91,15 +91,15 @@ fn drawDouble(alloc: Allocator, width: u32, thickness: u32) !CanvasAndOffset {
     canvas.rect(.{
         .x = 0,
         .y = 0,
-        .width = @floatFromInt(width),
-        .height = @floatFromInt(thickness),
+        .width = width,
+        .height = thickness,
     }, .on);
 
     canvas.rect(.{
         .x = 0,
-        .y = @floatFromInt(thickness * 2),
-        .width = @floatFromInt(width),
-        .height = @floatFromInt(thickness),
+        .y = thickness * 2,
+        .width = width,
+        .height = thickness,
     }, .on);
 
     const offset_y: i32 = -@as(i32, @intCast(thickness));
@@ -121,10 +121,10 @@ fn drawDotted(alloc: Allocator, width: u32, thickness: u32) !CanvasAndOffset {
         const x = @min(i * (dot_width + gap_width), width - 1);
         const rect_width = @min(width - x, dot_width);
         canvas.rect(.{
-            .x = @floatFromInt(x),
+            .x = @intCast(x),
             .y = 0,
-            .width = @floatFromInt(rect_width),
-            .height = @floatFromInt(thickness),
+            .width = rect_width,
+            .height = thickness,
         }, .on);
     }
 
@@ -146,10 +146,10 @@ fn drawDashed(alloc: Allocator, width: u32, thickness: u32) !CanvasAndOffset {
         const x = @min(i * dash_width, width - 1);
         const rect_width = @min(width - x, dash_width);
         canvas.rect(.{
-            .x = @floatFromInt(x),
+            .x = @intCast(x),
             .y = 0,
-            .width = @floatFromInt(rect_width),
-            .height = @floatFromInt(thickness),
+            .width = rect_width,
+            .height = thickness,
         }, .on);
     }