tests/gm/overfill.cpp

/*
 * Copyright 2025 Rive
 */

#include "gm.hpp"
#include "gmutils.hpp"
#include "rive/renderer.hpp"

using namespace rivegm;
using namespace rive;

// Check that clockwise paths render & blend correctly with winding numbers much
// larger than 1.
// It's especially important to check that clockwise render modes with
// transparency don't corrupt the paint after coverage is fully saturated.
static void render_overdraw_paths(RenderPaintStyle style,
                                  ColorInt color0,
                                  BlendMode mode0,
                                  ColorInt color1,
                                  BlendMode mode1,
                                  ColorInt color2,
                                  BlendMode mode2,
                                  Renderer* renderer)
{
    {
        // Create a region of solid dstColor to make sure we also catch the
        // blend modes on a==1.
        Paint solidWhite;
        solidWhite->color(0xffffffff);
        Path path;
        path->fillRule(FillRule::evenOdd);
        path->moveTo(10, 70);
        path->lineTo(130, 70);
        path->lineTo(130, 190);
        path->lineTo(10, 190);
        renderer->drawPath(path.get(), solidWhite.get());
    }

    PathBuilder pathBuilder;
    pathBuilder.fillRule(FillRule::clockwise);
    for (float r : {10, 50, 40, 80, 90, 70, 60, 20, 50, 30})
    {
        pathBuilder.addCircle(100, 100, r);
    }
    auto path = pathBuilder.detach();

    Paint paint;
    paint->style(style);
    paint->thickness(20);
    paint->color(color0);
    paint->blendMode(mode0);
    renderer->translate(-30, -30);
    renderer->drawPath(path.get(), paint.get());

    paint->color(color1);
    paint->blendMode(mode1);
    renderer->translate(60, 0);
    renderer->drawPath(path.get(), paint.get());

    paint->color(color2);
    paint->blendMode(mode2);
    renderer->translate(0, 60);
    renderer->drawPath(path.get(), paint.get());
}

DEF_SIMPLE_GM(overfill_opaque, 200, 200, renderer)
{
    render_overdraw_paths(RenderPaintStyle::fill,
                          0xff00ff00,
                          BlendMode::srcOver,
                          0xff0000ff,
                          BlendMode::srcOver,
                          0xffff0000,
                          BlendMode::srcOver,
                          renderer);
}

DEF_SIMPLE_GM(overfill_transparent, 200, 200, renderer)
{
    render_overdraw_paths(RenderPaintStyle::fill,
                          0x6000ff00,
                          BlendMode::srcOver,
                          0x600000ff,
                          BlendMode::srcOver,
                          0x60ff0000,
                          BlendMode::srcOver,
                          renderer);
}

DEF_SIMPLE_GM_WITH_CLEAR_COLOR(overfill_blendmodes,
                               0x20202020,
                               200,
                               200,
                               renderer)
{
    render_overdraw_paths(RenderPaintStyle::fill,
                          // Make one opaque so we catch early out
                          // optimizations.
                          0xff10f040,
                          BlendMode::exclusion,
                          0x70ee905a,
                          BlendMode::saturation,
                          0xb0905aee,
                          BlendMode::luminosity,
                          renderer);
}

DEF_SIMPLE_GM(overstroke_opaque, 200, 200, renderer)
{
    render_overdraw_paths(RenderPaintStyle::stroke,
                          0xff00ff00,
                          BlendMode::srcOver,
                          0xff0000ff,
                          BlendMode::srcOver,
                          0xffff0000,
                          BlendMode::srcOver,
                          renderer);
}

DEF_SIMPLE_GM(overstroke_transparent, 200, 200, renderer)
{
    render_overdraw_paths(RenderPaintStyle::stroke,
                          0x6000ff00,
                          BlendMode::srcOver,
                          0x600000ff,
                          BlendMode::srcOver,
                          0x60ff0000,
                          BlendMode::srcOver,
                          renderer);
}

DEF_SIMPLE_GM_WITH_CLEAR_COLOR(overstroke_blendmodes,
                               0x20202020,
                               200,
                               200,
                               renderer)
{
    render_overdraw_paths(RenderPaintStyle::stroke,
                          // Make one opaque so we catch early out
                          // optimizations.
                          0xff10f040,
                          BlendMode::exclusion,
                          0x70ee905a,
                          BlendMode::saturation,
                          0xb0905aee,
                          BlendMode::luminosity,
                          renderer);
}