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panopainter/tests/paint/blend_tests.cpp

144 lines
6.3 KiB
C++

#include "paint/blend.h"
#include "test_harness.h"
#include <cmath>
#include <string_view>
using pp::paint::BlendMode;
using pp::paint::Rgba;
using pp::paint::StrokeBlendMode;
using pp::paint::blend_mode_name;
using pp::paint::blend_pixels;
using pp::paint::blend_stroke_alpha;
using pp::paint::stroke_blend_mode_name;
namespace {
bool near(float a, float b)
{
return std::fabs(a - b) < 0.0001F;
}
void normal_blend_matches_source_over_alpha(pp::tests::Harness& h)
{
const auto result = blend_pixels(
Rgba { .r = 0.2F, .g = 0.4F, .b = 0.6F, .a = 0.5F },
Rgba { .r = 0.8F, .g = 0.2F, .b = 0.1F, .a = 0.25F },
BlendMode::normal);
PP_EXPECT(h, near(result.a, 0.625F));
PP_EXPECT(h, near(result.r, 0.44F));
PP_EXPECT(h, near(result.g, 0.32F));
PP_EXPECT(h, near(result.b, 0.4F));
}
void zero_alpha_stroke_leaves_base_unchanged(pp::tests::Harness& h)
{
const Rgba base { .r = 0.2F, .g = 0.3F, .b = 0.4F, .a = 0.5F };
const auto result = blend_pixels(
base,
Rgba { .r = 1.0F, .g = 1.0F, .b = 1.0F, .a = 0.0F },
BlendMode::screen);
PP_EXPECT(h, near(result.r, base.r));
PP_EXPECT(h, near(result.g, base.g));
PP_EXPECT(h, near(result.b, base.b));
PP_EXPECT(h, near(result.a, base.a));
}
void multiply_and_screen_are_bounded(pp::tests::Harness& h)
{
const Rgba base { .r = 0.25F, .g = 0.5F, .b = 0.75F, .a = 1.0F };
const Rgba stroke { .r = 0.5F, .g = 0.5F, .b = 0.5F, .a = 1.0F };
const auto multiply = blend_pixels(base, stroke, BlendMode::multiply);
const auto screen = blend_pixels(base, stroke, BlendMode::screen);
PP_EXPECT(h, near(multiply.r, 0.125F));
PP_EXPECT(h, near(multiply.g, 0.25F));
PP_EXPECT(h, near(multiply.b, 0.375F));
PP_EXPECT(h, near(screen.r, 0.625F));
PP_EXPECT(h, near(screen.g, 0.75F));
PP_EXPECT(h, near(screen.b, 0.875F));
}
void color_dodge_and_overlay_handle_extremes(pp::tests::Harness& h)
{
const auto dodge = blend_pixels(
Rgba { .r = 0.4F, .g = 0.5F, .b = 0.6F, .a = 1.0F },
Rgba { .r = 1.0F, .g = 0.5F, .b = 0.0F, .a = 1.0F },
BlendMode::color_dodge);
const auto overlay = blend_pixels(
Rgba { .r = 0.25F, .g = 0.5F, .b = 0.75F, .a = 1.0F },
Rgba { .r = 0.5F, .g = 0.5F, .b = 0.5F, .a = 1.0F },
BlendMode::overlay);
PP_EXPECT(h, near(dodge.r, 1.0F));
PP_EXPECT(h, near(dodge.g, 1.0F));
PP_EXPECT(h, near(dodge.b, 0.6F));
PP_EXPECT(h, near(overlay.r, 0.25F));
PP_EXPECT(h, near(overlay.g, 0.5F));
PP_EXPECT(h, near(overlay.b, 0.75F));
}
void clamps_inputs_and_names_modes(pp::tests::Harness& h)
{
const auto result = blend_pixels(
Rgba { .r = -1.0F, .g = 2.0F, .b = 0.5F, .a = 2.0F },
Rgba { .r = 2.0F, .g = -1.0F, .b = 0.5F, .a = 2.0F },
BlendMode::normal);
PP_EXPECT(h, near(result.r, 1.0F));
PP_EXPECT(h, near(result.g, 0.0F));
PP_EXPECT(h, near(result.b, 0.5F));
PP_EXPECT(h, near(result.a, 1.0F));
PP_EXPECT(h, blend_mode_name(BlendMode::overlay) == std::string_view("overlay"));
}
void stroke_alpha_blend_modes_match_shader_reference_vectors(pp::tests::Harness& h)
{
PP_EXPECT(h, near(blend_stroke_alpha(0.2F, 0.8F, 0.25F, StrokeBlendMode::normal), 0.35F));
PP_EXPECT(h, near(blend_stroke_alpha(0.6F, 0.5F, 1.0F, StrokeBlendMode::multiply), 0.3F));
PP_EXPECT(h, near(blend_stroke_alpha(0.6F, 0.2F, 1.0F, StrokeBlendMode::subtract), 0.4F));
PP_EXPECT(h, near(blend_stroke_alpha(0.6F, 0.2F, 1.0F, StrokeBlendMode::darken), 0.2F));
PP_EXPECT(h, near(blend_stroke_alpha(0.75F, 0.25F, 1.0F, StrokeBlendMode::overlay), 0.625F));
PP_EXPECT(h, near(blend_stroke_alpha(0.4F, 0.5F, 1.0F, StrokeBlendMode::color_dodge), 0.8F));
PP_EXPECT(h, near(blend_stroke_alpha(0.6F, 0.5F, 1.0F, StrokeBlendMode::color_burn), 0.2F));
PP_EXPECT(h, near(blend_stroke_alpha(0.75F, 0.5F, 1.0F, StrokeBlendMode::linear_burn), 0.25F));
PP_EXPECT(h, near(blend_stroke_alpha(0.2F, 0.2F, 1.0F, StrokeBlendMode::hard_mix), 0.0F));
PP_EXPECT(h, near(blend_stroke_alpha(0.7F, 0.8F, 1.0F, StrokeBlendMode::hard_mix), 1.0F));
PP_EXPECT(h, near(blend_stroke_alpha(0.5F, 0.25F, 0.16F, StrokeBlendMode::linear_height), 0.637170F));
PP_EXPECT(h, near(blend_stroke_alpha(0.5F, 0.25F, 0.16F, StrokeBlendMode::height), 0.228217F));
}
void stroke_alpha_blend_modes_handle_edges_and_names(pp::tests::Harness& h)
{
PP_EXPECT(h, near(blend_stroke_alpha(0.8F, 0.2F, 0.0F, StrokeBlendMode::multiply), 0.8F));
PP_EXPECT(h, near(blend_stroke_alpha(0.0F, 0.8F, 1.0F, StrokeBlendMode::color_dodge), 0.0F));
PP_EXPECT(h, near(blend_stroke_alpha(0.8F, 1.0F, 1.0F, StrokeBlendMode::color_dodge), 1.0F));
PP_EXPECT(h, near(blend_stroke_alpha(1.0F, 0.2F, 1.0F, StrokeBlendMode::color_burn), 1.0F));
PP_EXPECT(h, near(blend_stroke_alpha(0.8F, 0.0F, 1.0F, StrokeBlendMode::color_burn), 0.0F));
PP_EXPECT(h, near(blend_stroke_alpha(0.0F, 1.0F, 1.0F, StrokeBlendMode::hard_mix), 0.0F));
PP_EXPECT(h, near(blend_stroke_alpha(-1.0F, 2.0F, 2.0F, StrokeBlendMode::normal), 1.0F));
PP_EXPECT(h, near(blend_stroke_alpha(0.2F, 0.2F, 0.5F, static_cast<StrokeBlendMode>(255)), 1.0F));
PP_EXPECT(h, stroke_blend_mode_name(StrokeBlendMode::normal) == std::string_view("normal"));
PP_EXPECT(h, stroke_blend_mode_name(StrokeBlendMode::linear_height) == std::string_view("linear_height"));
PP_EXPECT(h, stroke_blend_mode_name(StrokeBlendMode::height) == std::string_view("height"));
PP_EXPECT(h, stroke_blend_mode_name(static_cast<StrokeBlendMode>(255)) == std::string_view("unknown"));
}
}
int main()
{
pp::tests::Harness harness;
harness.run("normal_blend_matches_source_over_alpha", normal_blend_matches_source_over_alpha);
harness.run("zero_alpha_stroke_leaves_base_unchanged", zero_alpha_stroke_leaves_base_unchanged);
harness.run("multiply_and_screen_are_bounded", multiply_and_screen_are_bounded);
harness.run("color_dodge_and_overlay_handle_extremes", color_dodge_and_overlay_handle_extremes);
harness.run("clamps_inputs_and_names_modes", clamps_inputs_and_names_modes);
harness.run("stroke_alpha_blend_modes_match_shader_reference_vectors", stroke_alpha_blend_modes_match_shader_reference_vectors);
harness.run("stroke_alpha_blend_modes_handle_edges_and_names", stroke_alpha_blend_modes_handle_edges_and_names);
return harness.finish();
}