Files
MagicSetEditor2/src/gfx/image_effects.cpp
T
2017-01-18 08:52:57 -06:00

113 lines
3.9 KiB
C++

//+----------------------------------------------------------------------------+
//| Description: Magic Set Editor - Program to make Magic (tm) cards |
//| Copyright: (C) 2001 - 2017 Twan van Laarhoven and Sean Hunt |
//| License: GNU General Public License 2 or later (see file COPYING) |
//+----------------------------------------------------------------------------+
// ----------------------------------------------------------------------------- : Includes
#include <util/prec.hpp>
#include <gfx/gfx.hpp>
#include <util/error.hpp>
// ----------------------------------------------------------------------------- : Saturation
void saturate(Image& image, double amount) {
Byte* pix = image.GetData();
Byte* end = pix + image.GetWidth() * image.GetHeight() * 3;
// the formula for saturation is
// rgb' = (rgb - amount * avg) / (1 - amount)
// if amount >= 1 then this is some kind of inversion
// if amount > 0 then use formula directly
// if amount < 0 then de-saturate instead:
// rgb = rgb' + -amount*avg - -amount*rgb'
// = rgb' * (1 - -amount) + -amount*avg
// if amount < -1 then we are left with just the average
int factor = int(256 * amount);
if (factor == 0) {
return; // nothing to do
} else if (factor == 256) {
// super crazy saturation: division by zero
// if we take infty to be 255, then it is a >avg test
while (pix != end) {
int r = pix[0], g = pix[1], b = pix[2];
pix[0] = r+r > g+b ? 255 : 0;
pix[1] = g+g > b+r ? 255 : 0;
pix[2] = b+b > r+g ? 255 : 0;
pix += 3;
}
} else if (factor > 0) {
int div = 768 - 3 * factor;
assert(div > 0);
while (pix != end) {
int r = pix[0], g = pix[1], b = pix[2];
int avg = factor*(r+g+b);
pix[0] = col((768*r - avg) / div);
pix[1] = col((768*g - avg) / div);
pix[2] = col((768*b - avg) / div);
pix += 3;
}
} else {
int factor1 = -factor;
int factor2 = 768 - 3*factor1;
while (pix != end) {
int r = pix[0], g = pix[1], b = pix[2];
int avg = factor1*(r+g+b);
pix[0] = (factor2*r + avg) / 768;
pix[1] = (factor2*g + avg) / 768;
pix[2] = (factor2*b + avg) / 768;
pix += 3;
}
}
}
// ----------------------------------------------------------------------------- : Color inversion
void invert(Image& img) {
Byte* data = img.GetData();
int n = 3 * img.GetWidth() * img.GetHeight();
for (int i = 0 ; i < n ; ++i) {
data[i] = 255 - data[i];
}
}
// ----------------------------------------------------------------------------- : Coloring symbol images
RGB recolor(RGB x, RGB cr, RGB cg, RGB cb, RGB cw) {
int lo = min(x.r,min(x.g,x.b));
// amount of each
int nr = x.r - lo;
int ng = x.g - lo;
int nb = x.b - lo;
int nw = lo;
// We should have that nr+ng+bw+nw < 255,
// otherwise the input is not a mixture of red/green/blue/white.
// Just to be sure, divide by the sum instead of 255
int total = max(255, nr+ng+nb+nw);
return RGB(
static_cast<Byte>( (nr * cr.r + ng * cg.r + nb * cb.r + nw * cw.r) / total ),
static_cast<Byte>( (nr * cr.g + ng * cg.g + nb * cb.g + nw * cw.g) / total ),
static_cast<Byte>( (nr * cr.b + ng * cg.b + nb * cb.b + nw * cw.b) / total )
);
}
void recolor(Image& img, RGB cr, RGB cg, RGB cb, RGB cw) {
RGB* data = (RGB*)img.GetData();
int n = img.GetWidth() * img.GetHeight();
for (int i = 0 ; i < n ; ++i) {
data[i] = recolor(data[i], cr, cg, cb, cw);
}
}
Byte to_grayscale(RGB x) {
return (Byte)((6969 * x.r + 23434 * x.g + 2365 * x.b) / 32768); // from libpng
}
void recolor(Image& img, RGB cr) {
RGB black(0,0,0), white(255,255,255);
bool dark = to_grayscale(cr) < 100;
recolor(img, cr, dark ? black : white, dark ? white : black, white);
}