106 lines
3.4 KiB
C++
106 lines
3.4 KiB
C++
#include "paint/blend.h"
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#include "test_harness.h"
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#include <cmath>
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#include <string_view>
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using pp::paint::BlendMode;
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using pp::paint::Rgba;
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using pp::paint::blend_mode_name;
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using pp::paint::blend_pixels;
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namespace {
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bool near(float a, float b)
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{
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return std::fabs(a - b) < 0.0001F;
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}
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void normal_blend_matches_source_over_alpha(pp::tests::Harness& h)
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{
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const auto result = blend_pixels(
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Rgba { .r = 0.2F, .g = 0.4F, .b = 0.6F, .a = 0.5F },
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Rgba { .r = 0.8F, .g = 0.2F, .b = 0.1F, .a = 0.25F },
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BlendMode::normal);
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PP_EXPECT(h, near(result.a, 0.625F));
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PP_EXPECT(h, near(result.r, 0.44F));
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PP_EXPECT(h, near(result.g, 0.32F));
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PP_EXPECT(h, near(result.b, 0.4F));
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}
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void zero_alpha_stroke_leaves_base_unchanged(pp::tests::Harness& h)
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{
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const Rgba base { .r = 0.2F, .g = 0.3F, .b = 0.4F, .a = 0.5F };
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const auto result = blend_pixels(
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base,
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Rgba { .r = 1.0F, .g = 1.0F, .b = 1.0F, .a = 0.0F },
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BlendMode::screen);
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PP_EXPECT(h, near(result.r, base.r));
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PP_EXPECT(h, near(result.g, base.g));
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PP_EXPECT(h, near(result.b, base.b));
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PP_EXPECT(h, near(result.a, base.a));
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}
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void multiply_and_screen_are_bounded(pp::tests::Harness& h)
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{
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const Rgba base { .r = 0.25F, .g = 0.5F, .b = 0.75F, .a = 1.0F };
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const Rgba stroke { .r = 0.5F, .g = 0.5F, .b = 0.5F, .a = 1.0F };
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const auto multiply = blend_pixels(base, stroke, BlendMode::multiply);
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const auto screen = blend_pixels(base, stroke, BlendMode::screen);
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PP_EXPECT(h, near(multiply.r, 0.125F));
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PP_EXPECT(h, near(multiply.g, 0.25F));
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PP_EXPECT(h, near(multiply.b, 0.375F));
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PP_EXPECT(h, near(screen.r, 0.625F));
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PP_EXPECT(h, near(screen.g, 0.75F));
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PP_EXPECT(h, near(screen.b, 0.875F));
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}
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void color_dodge_and_overlay_handle_extremes(pp::tests::Harness& h)
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{
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const auto dodge = blend_pixels(
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Rgba { .r = 0.4F, .g = 0.5F, .b = 0.6F, .a = 1.0F },
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Rgba { .r = 1.0F, .g = 0.5F, .b = 0.0F, .a = 1.0F },
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BlendMode::color_dodge);
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const auto overlay = blend_pixels(
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Rgba { .r = 0.25F, .g = 0.5F, .b = 0.75F, .a = 1.0F },
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Rgba { .r = 0.5F, .g = 0.5F, .b = 0.5F, .a = 1.0F },
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BlendMode::overlay);
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PP_EXPECT(h, near(dodge.r, 1.0F));
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PP_EXPECT(h, near(dodge.g, 1.0F));
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PP_EXPECT(h, near(dodge.b, 0.6F));
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PP_EXPECT(h, near(overlay.r, 0.25F));
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PP_EXPECT(h, near(overlay.g, 0.5F));
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PP_EXPECT(h, near(overlay.b, 0.75F));
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}
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void clamps_inputs_and_names_modes(pp::tests::Harness& h)
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{
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const auto result = blend_pixels(
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Rgba { .r = -1.0F, .g = 2.0F, .b = 0.5F, .a = 2.0F },
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Rgba { .r = 2.0F, .g = -1.0F, .b = 0.5F, .a = 2.0F },
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BlendMode::normal);
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PP_EXPECT(h, near(result.r, 1.0F));
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PP_EXPECT(h, near(result.g, 0.0F));
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PP_EXPECT(h, near(result.b, 0.5F));
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PP_EXPECT(h, near(result.a, 1.0F));
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PP_EXPECT(h, blend_mode_name(BlendMode::overlay) == std::string_view("overlay"));
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}
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}
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int main()
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{
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pp::tests::Harness harness;
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harness.run("normal_blend_matches_source_over_alpha", normal_blend_matches_source_over_alpha);
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harness.run("zero_alpha_stroke_leaves_base_unchanged", zero_alpha_stroke_leaves_base_unchanged);
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harness.run("multiply_and_screen_are_bounded", multiply_and_screen_are_bounded);
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harness.run("color_dodge_and_overlay_handle_extremes", color_dodge_and_overlay_handle_extremes);
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harness.run("clamps_inputs_and_names_modes", clamps_inputs_and_names_modes);
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return harness.finish();
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}
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