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Fix bug in Saturation layer blend mode (fix #2661)

This commit is contained in:
Gaspar Capello 2025-08-25 14:32:46 -03:00 committed by David Capello
parent f61c2c3950
commit 0995e72a6f
1 changed files with 10 additions and 64 deletions
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74
src/doc/blend_funcs.cpp
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@ -1,5 +1,5 @@
// Aseprite Document Library
// Copyright (c) 2019-2022 Igara Studio S.A.
// Copyright (c) 2019-2025 Igara Studio S.A.
// Copyright (c) 2001-2017 David Capello
//
// This file is released under the terms of the MIT license.
@ -397,73 +397,19 @@ static void set_lum(double& r, double& g, double& b, double l)
clip_color(r, g, b);
}
static inline uint8_t get_imin_channel(const double r, const double g, const double b)
{
// We use '<=' to get min so as to catch two channels being equal
if (r <= g && r <= b)
return 0b001;
if (g <= r && g <= b)
return 0b010;
return 0b100;
}
static inline uint8_t get_imax_channel(const double r, const double g, const double b)
{
if (r > g && r > b)
return 0b001;
if (g > r && g > b)
return 0b010;
return 0b100;
}
static inline uint8_t get_imid_channel(uint8_t imin, uint8_t imax)
{
// Getting the remaining channel through exclusion guarantees that it is neither min nor max
return (~(imax | imin)) & 0b111;
}
static inline double& index_to_ref(double& r, double& g, double& b, uint8_t i)
{
if (i == 0b001)
return r;
if (i == 0b010)
return g;
return b;
}
// TODO replace this with a better impl (and test this, not sure if it's correct)
static void set_sat(double& r, double& g, double& b, double s)
{
#undef MIN
#undef MAX
#undef MID
#define MIN(x, y) (((x) < (y)) ? (x) : (y))
#define MAX(x, y) (((x) > (y)) ? (x) : (y))
#define MID(x, y, z) \
((x) > (y) ? ((y) > (z) ? (y) : ((x) > (z) ? (z) : (x))) : \
((y) > (z) ? ((z) > (x) ? (z) : (x)) : (y)))
const double minv = std::min(std::min(r, g), b);
const double maxv = std::max(std::max(r, g), b);
const double range = maxv - minv;
// Fetch channel indices
const uint8_t imin = get_imin_channel(r, g, b);
const uint8_t imax = get_imax_channel(r, g, b);
const uint8_t imid = get_imid_channel(imin, imax);
// Map the indices for each channel to references
double& min = index_to_ref(r, g, b, imin);
double& max = index_to_ref(r, g, b, imax);
double& mid = index_to_ref(r, g, b, imid);
if (max > min) {
mid = ((mid - min) * s) / (max - min);
max = s;
if (range > 0.0) {
r = ((r - minv) * s) / range;
g = ((g - minv) * s) / range;
b = ((b - minv) * s) / range;
}
else
mid = max = 0;
min = 0;
r = g = b = 0.0;
}
color_t rgba_blender_hsl_hue(color_t backdrop, color_t src, int opacity)
@ -552,7 +498,7 @@ color_t rgba_blender_subtract(color_t backdrop, color_t src, int opacity)
int r = rgba_getr(backdrop) - rgba_getr(src);
int g = rgba_getg(backdrop) - rgba_getg(src);
int b = rgba_getb(backdrop) - rgba_getb(src);
src = rgba(MAX(r, 0), MAX(g, 0), MAX(b, 0), 0) | (src & rgba_a_mask);
src = rgba(std::max(r, 0), std::max(g, 0), std::max(b, 0), 0) | (src & rgba_a_mask);
return rgba_blender_normal(backdrop, src, opacity);
}