Merge pull request #49 from vancluever/transformations

Transformation support

spec/003_fill_triangle.zig

@@ -2,7 +2,6 @@
 //   Copyright © 2024 Chris Marchesi
 
 //! Case: Renders and fills a triangle on a 300x300 surface.
-const debug = @import("std").debug;
 const mem = @import("std").mem;
 
 const z2d = @import("z2d");

spec/004_fill_square.zig

@@ -2,7 +2,6 @@
 //   Copyright © 2024 Chris Marchesi
 
 //! Case: Renders and fills a square on a 300x300 surface.
-const debug = @import("std").debug;
 const mem = @import("std").mem;
 
 const z2d = @import("z2d");

spec/005_fill_trapezoid.zig

@@ -2,7 +2,6 @@
 //   Copyright © 2024 Chris Marchesi
 
 //! Case: Renders and fills a trapezoid on a 300x300 surface.
-const debug = @import("std").debug;
 const mem = @import("std").mem;
 
 const z2d = @import("z2d");

spec/006_fill_star_even_odd.zig

@@ -5,7 +5,6 @@
 //!
 //! NOTE: This star fills with even-odd rule, so it's expected for there to be
 //! a gap in the middle.
-const debug = @import("std").debug;
 const mem = @import("std").mem;
 
 const z2d = @import("z2d");

spec/007_fill_bezier.zig

@@ -2,7 +2,6 @@
 //   Copyright © 2024 Chris Marchesi
 
 //! Case: Renders and fills a bezier curve on a 300x300 surface.
-const debug = @import("std").debug;
 const mem = @import("std").mem;
 
 const z2d = @import("z2d");

spec/008_stroke_triangle.zig

@@ -2,7 +2,6 @@
 //   Copyright © 2024 Chris Marchesi
 
 //! Case: Renders and strokes a triangle on a 300x300 surface.
-const debug = @import("std").debug;
 const mem = @import("std").mem;
 
 const z2d = @import("z2d");

spec/009_stroke_square.zig

@@ -2,7 +2,6 @@
 //   Copyright © 2024 Chris Marchesi
 
 //! Case: Renders and strokes a square on a 300x300 surface.
-const debug = @import("std").debug;
 const mem = @import("std").mem;
 
 const z2d = @import("z2d");

spec/010_stroke_trapezoid.zig

@@ -2,7 +2,6 @@
 //   Copyright © 2024 Chris Marchesi
 
 //! Case: Renders and strokes a trapezoid on a 300x300 surface.
-const debug = @import("std").debug;
 const mem = @import("std").mem;
 
 const z2d = @import("z2d");

spec/011_stroke_star.zig

@@ -6,7 +6,6 @@
 //! Note that this test also validates that we always fill strokes using the
 //! non-zero rule, since drawing a star means tracing a path that overlaps as
 //! you move from point to point.
-const debug = @import("std").debug;
 const mem = @import("std").mem;
 
 const z2d = @import("z2d");

spec/012_stroke_bezier.zig

@@ -5,7 +5,6 @@
 //! surface.
 //!
 //! The beziers are not closed.
-const debug = @import("std").debug;
 const mem = @import("std").mem;
 
 const z2d = @import("z2d");

spec/013_fill_combined.zig

@@ -3,7 +3,6 @@
 
 //! Case: Renders and fills multiple shapes using a single path operation, used
 //! to ensure we can do this without having to fill each polygon individually.
-const debug = @import("std").debug;
 const mem = @import("std").mem;
 
 const z2d = @import("z2d");

spec/014_stroke_lines.zig

@@ -3,7 +3,6 @@
 
 //! Case: Renders multiple lines with the default thickness in different
 //! directions, unclosed.
-const debug = @import("std").debug;
 const mem = @import("std").mem;
 
 const z2d = @import("z2d");

spec/015_stroke_miter.zig

@@ -2,7 +2,6 @@
 //   Copyright © 2024 Chris Marchesi
 
 //! Case: Renders unclosed lines with miters.
-const debug = @import("std").debug;
 const mem = @import("std").mem;
 
 const z2d = @import("z2d");

spec/016_fill_star_non_zero.zig

@@ -5,7 +5,6 @@
 //!
 //! NOTE: This star explicitly fills with non-zero rule, so it's expected for
 //! there to NOT be a gap in the middle.
-const debug = @import("std").debug;
 const mem = @import("std").mem;
 
 const z2d = @import("z2d");

spec/017_stroke_star_round.zig

@@ -2,7 +2,6 @@
 //   Copyright © 2024 Chris Marchesi
 
 //! Case: Renders and strokes a star on a 300x300 surface with rounded corners.
-const debug = @import("std").debug;
 const mem = @import("std").mem;
 
 const z2d = @import("z2d");

spec/018_stroke_square_spiral_round.zig

@@ -2,7 +2,6 @@
 //   Copyright © 2024 Chris Marchesi
 
 //! Case: Renders unclosed lines with rounded joins.
-const debug = @import("std").debug;
 const mem = @import("std").mem;
 
 const z2d = @import("z2d");

spec/019_stroke_bevel_miterlimit.zig

@@ -3,7 +3,6 @@
 
 //! Case: Renders multiple cornered lines with bevels and miters, the latter
 //! with varying miter limits.
-const debug = @import("std").debug;
 const mem = @import("std").mem;
 
 const z2d = @import("z2d");

spec/020_stroke_lines_round_caps.zig

@@ -2,7 +2,6 @@
 //   Copyright © 2024 Chris Marchesi
 
 //! Case: Renders multiple lines, round-capped, in various directions.
-const debug = @import("std").debug;
 const mem = @import("std").mem;
 
 const z2d = @import("z2d");

spec/021_stroke_lines_square_caps.zig

@@ -2,7 +2,6 @@
 //   Copyright © 2024 Chris Marchesi
 
 //! Case: Renders multiple lines, square-capped, in various directions.
-const debug = @import("std").debug;
 const mem = @import("std").mem;
 
 const z2d = @import("z2d");

spec/022_stroke_lines_butt_caps.zig

@@ -2,7 +2,6 @@
 //   Copyright © 2024 Chris Marchesi
 
 //! Case: Renders multiple lines, butt-capped, in various directions.
-const debug = @import("std").debug;
 const mem = @import("std").mem;
 
 const z2d = @import("z2d");

spec/024_fill_triangle_direct_cross_format.zig

@@ -4,7 +4,6 @@
 //! Case: Renders and fills a triangle on a 300x300 surface, but with different
 //! pixel types (RGBA on RGB surface) We expect compositing to work on both
 //! main AA modes (no AA, default AA).
-const debug = @import("std").debug;
 const mem = @import("std").mem;
 
 const z2d = @import("z2d");

spec/025_fill_diamond_clipped.zig

@@ -2,7 +2,6 @@
 //   Copyright © 2024 Chris Marchesi
 
 //! Case: Renders and fills a diamond clipped on a 300x300 surface.
-const debug = @import("std").debug;
 const mem = @import("std").mem;
 
 const z2d = @import("z2d");

spec/026_fill_triangle_full.zig

@@ -3,7 +3,6 @@
 
 //! Case: Renders and fills a triangle on a 300x300 surface, extended to the
 //! full canvas.
-const debug = @import("std").debug;
 const mem = @import("std").mem;
 
 const z2d = @import("z2d");

spec/027_stroke_bezier_tolerance.zig

@@ -5,7 +5,6 @@
 //! surface, at varying levels of error tolerance.
 //!
 //! The beziers are not closed.
-const debug = @import("std").debug;
 const mem = @import("std").mem;
 
 const z2d = @import("z2d");

spec/029_stroke_lines_round_caps_tolerance.zig

@@ -2,7 +2,6 @@
 //   Copyright © 2024 Chris Marchesi
 
 //! Case: Renders multiple lines, round-capped at varying levels of tolerance.
-const debug = @import("std").debug;
 const mem = @import("std").mem;
 
 const z2d = @import("z2d");

spec/030_stroke_star_round_tolerance.zig

@@ -3,7 +3,6 @@
 
 //! Case: Renders and strokes stars on a 900x300 surface with rounded corners,
 //! and varying tolerance.
-const debug = @import("std").debug;
 const mem = @import("std").mem;
 
 const z2d = @import("z2d");

spec/031_fill_quad_bezier.zig

@@ -14,7 +14,6 @@
 //! the one that you'd set with moveTo) and the final point are technically the
 //! start and end points. Thus, to get a proper quadratic to what you'd expect,
 //! you need the *control* points (so (x1, y1), (x2, y2)) to be equal.
-const debug = @import("std").debug;
 const mem = @import("std").mem;
 
 const z2d = @import("z2d");

spec/032_fill_arc.zig

@@ -3,7 +3,6 @@
 
 //! Case: Renders arcs as a demonstration of how this can be done with bezier
 //! primitives.
-const debug = @import("std").debug;
 const mem = @import("std").mem;
 
 const z2d = @import("z2d");

spec/033_fill_zig_mark.zig

@@ -6,7 +6,6 @@
 //!
 //! The [Zig logo](https://github.com/ziglang/logo) and logomark are licensed
 //! CC-BY-SA 4.0.
-const debug = @import("std").debug;
 const mem = @import("std").mem;
 
 const z2d = @import("z2d");

spec/034_stroke_cross.zig

@@ -3,7 +3,6 @@
 
 //! Case: Renders a stroked cross (used to validate correct join direction for
 //! strokes when changing direction (clockwise -> counter-clockwise and vice versa).
-const debug = @import("std").debug;
 const mem = @import("std").mem;
 
 const z2d = @import("z2d");

spec/035_arc_command.zig

@@ -7,7 +7,6 @@
 //! https://www.w3.org/TR/SVG11/paths.html#PathDataEllipticalArcCommands.
 //! Copyright © 2011 World Wide Web Consortium.
 //! https://www.w3.org/copyright/software-license-2023/
-const debug = @import("std").debug;
 const math = @import("std").math;
 const mem = @import("std").mem;
 

spec/036_stroke_colinear.zig

@@ -2,7 +2,6 @@
 //   Copyright © 2024 Chris Marchesi
 
 //! Case: Asserts correctness in colinear stroke operations.
-const debug = @import("std").debug;
 const mem = @import("std").mem;
 
 const z2d = @import("z2d");

spec/037_stroke_join_overlap.zig

@@ -3,7 +3,6 @@
 
 //! Case: Draws overlapping strokes in different directions to test that joins
 //! with extremely acute angles overlap properly.
-const debug = @import("std").debug;
 const mem = @import("std").mem;
 
 const z2d = @import("z2d");

spec/038_stroke_zero_length.zig

@@ -2,7 +2,6 @@
 //   Copyright © 2024 Chris Marchesi
 
 //! Case: Renders and fills a triangle on a 300x300 surface.
-const debug = @import("std").debug;
 const mem = @import("std").mem;
 
 const z2d = @import("z2d");

spec/039_stroke_paint_extent_dontclip.zig

@@ -3,7 +3,6 @@
 
 //! Case: Ensures that certain extents don't get clipped on the larger
 //! y-boundary.
-const debug = @import("std").debug;
 const mem = @import("std").mem;
 
 const z2d = @import("z2d");

spec/040_stroke_corner_symmetrical.zig

@@ -4,7 +4,6 @@
 //! Case: ensures proper alignment of a line spanning the whole box diagonally.
 //! The line should be symmetrical on both the upper left and bottom right
 //! corners of the box.
-const debug = @import("std").debug;
 const mem = @import("std").mem;
 
 const z2d = @import("z2d");

spec/041_stroke_noop_lineto.zig

@@ -3,7 +3,6 @@
 
 //! Case: Ensure no-op (degenerate) lineto operations are accounted for
 //! properly and do not break strokes.
-const debug = @import("std").debug;
 const mem = @import("std").mem;
 
 const z2d = @import("z2d");

spec/042_arc_ellipses.zig

@@ -0,0 +1,92 @@
+// SPDX-License-Identifier: 0BSD
+//   Copyright © 2024 Chris Marchesi
+
+//! Case: Renders ellipses (fill and stroke) using arc commands and
+//! transformation matrices.
+const math = @import("std").math;
+const mem = @import("std").mem;
+
+const z2d = @import("z2d");
+
+pub const filename = "042_arc_ellipses";
+
+pub fn render(alloc: mem.Allocator, aa_mode: z2d.options.AntiAliasMode) !z2d.Surface {
+    const width = 400;
+    const height = 400;
+    const sfc = try z2d.Surface.init(.image_surface_rgb, alloc, width, height);
+
+    var context: z2d.Context = .{
+        .surface = sfc,
+        .pattern = .{
+            .opaque_pattern = .{
+                .pixel = .{ .rgb = .{ .r = 0xFF, .g = 0xFF, .b = 0xFF } }, // White on black
+            },
+        },
+        .anti_aliasing_mode = aa_mode,
+        .line_width = 5,
+    };
+
+    var path = z2d.Path.init(alloc);
+    defer path.deinit();
+    // Add a margin of (10, 10) by translation
+    path.transformation = path.transformation.translate(10, 10);
+    // first ellipse at 0, 0 rx = 50, ry=100
+    _ = try ellipse(&path, 0, 0, 50, 100);
+    try context.fill(alloc, path);
+
+    // second as the first, but stroked, at 100, 0)
+    _ = try ellipse(&path, 100, 0, 50, 100);
+    try context.stroke(alloc, path);
+
+    // as the second, but we capture the CTM to test stroke warping (at 200, 0)
+    var saved_ctm = context.transformation;
+    var saved_line_width = context.line_width;
+    context.transformation = try ellipse(&path, 200, 0, 50, 100);
+    context.line_width = lw: {
+        var ux = saved_line_width;
+        var uy = saved_line_width;
+        try context.transformation.deviceToUserDistance(&ux, &uy);
+        if (ux < uy) {
+            break :lw uy;
+        }
+        break :lw ux;
+    };
+    try context.stroke(alloc, path);
+    context.transformation = saved_ctm;
+    context.line_width = saved_line_width;
+
+    // as the third, but first rotate 45 degrees (at 300, 0)
+    const saved_path_ctm = path.transformation;
+    saved_ctm = context.transformation;
+    saved_line_width = context.line_width;
+    path.transformation = path.transformation.rotate(math.pi / 4.0);
+    context.transformation = try ellipse(&path, 300, 0, 50, 100);
+    context.line_width = lw: {
+        var ux = saved_line_width;
+        var uy = saved_line_width;
+        try context.transformation.deviceToUserDistance(&ux, &uy);
+        if (ux < uy) {
+            break :lw uy;
+        }
+        break :lw ux;
+    };
+    try context.stroke(alloc, path);
+    path.transformation = saved_path_ctm;
+    context.transformation = saved_ctm;
+    context.line_width = saved_line_width;
+
+    return sfc;
+}
+
+fn ellipse(path: *z2d.Path, x: f64, y: f64, rx: f64, ry: f64) !z2d.Transformation {
+    const saved_ctm = path.transformation;
+    path.reset();
+    path.transformation = path.transformation
+        .translate(x + rx / 2, y + ry / 2)
+        .scale(rx / 2, ry / 2);
+    try path.arc(0, 0, 1, 0, 2 * math.pi, false, null);
+    const effective_ctm = path.transformation;
+    path.transformation = saved_ctm;
+    try path.close();
+    return effective_ctm;
+}