Первая растеризация

src/render/cpu/ellipse.zig

@@ -0,0 +1,59 @@
+const std = @import("std");
+const Document = @import("../../models/Document.zig");
+const pipeline = @import("pipeline.zig");
+const DrawContext = pipeline.DrawContext;
+const Color = @import("dvui").Color;
+
+const Object = Document.Object;
+const default_stroke: Color.PMA = .{ .r = 0, .g = 0, .b = 0, .a = 255 };
+
+/// Рисует эллипс: центр (0,0), полуоси radii. Растеризация в координатах буфера (обводка кольцом).
+pub fn draw(ctx: *DrawContext, obj: *const Object) void {
+    const r_prop = obj.getProperty(.radii) orelse return;
+    const rx = r_prop.radii.x;
+    const ry = r_prop.radii.y;
+    if (rx <= 0 or ry <= 0) return;
+    const stroke = if (obj.getProperty(.stroke_rgba)) |s| pipeline.rgbaToPma(s.stroke_rgba) else default_stroke;
+
+    const corners = [_]struct { x: f32, y: f32 }{
+        .{ .x = -rx, .y = -ry },
+        .{ .x = rx, .y = -ry },
+        .{ .x = rx, .y = ry },
+        .{ .x = -rx, .y = ry },
+    };
+    const w0 = ctx.localToWorld(corners[0].x, corners[0].y);
+    const b0 = ctx.worldToBufferF(w0.x, w0.y);
+    var min_bx: f32 = b0.x;
+    var min_by: f32 = b0.y;
+    var max_bx: f32 = b0.x;
+    var max_by: f32 = b0.y;
+    for (corners[1..]) |c| {
+        const w = ctx.localToWorld(c.x, c.y);
+        const b = ctx.worldToBufferF(w.x, w.y);
+        min_bx = @min(min_bx, b.x);
+        min_by = @min(min_by, b.y);
+        max_bx = @max(max_bx, b.x);
+        max_by = @max(max_by, b.y);
+    }
+    const buf_w: i32 = @intCast(ctx.buf_width);
+    const buf_h: i32 = @intCast(ctx.buf_height);
+    const x0: i32 = @max(0, @as(i32, @intFromFloat(std.math.floor(min_bx))));
+    const y0: i32 = @max(0, @as(i32, @intFromFloat(std.math.floor(min_by))));
+    const x1: i32 = @min(buf_w, @as(i32, @intFromFloat(std.math.ceil(max_bx))) + 1);
+    const y1: i32 = @min(buf_h, @as(i32, @intFromFloat(std.math.ceil(max_by))) + 1);
+
+    var by: i32 = y0;
+    while (by < y1) : (by += 1) {
+        var bx: i32 = x0;
+        while (bx < x1) : (bx += 1) {
+            const w = ctx.bufferToWorld(@as(f32, @floatFromInt(bx)) + 0.5, @as(f32, @floatFromInt(by)) + 0.5);
+            const loc = ctx.worldToLocal(w.x, w.y);
+            const nx = loc.x / rx;
+            const ny = loc.y / ry;
+            const d = nx * nx + ny * ny;
+            if (d >= 0.9 and d <= 1.1) {
+                ctx.blendPixelAtBuffer(@intCast(bx), @intCast(by), stroke);
+            }
+        }
+    }
+}