113 lines
3.4 KiB
C
113 lines
3.4 KiB
C
|
|
||
|
|
#include "libimagequant.h"
|
||
|
|
#include "pam.h"
|
||
|
|
#include "blur.h"
|
||
|
|
|
||
|
|
/*
|
||
|
|
Blurs image horizontally (width 2*size+1) and writes it transposed to dst (called twice gives 2d blur)
|
||
|
|
*/
|
||
|
|
static void transposing_1d_blur(unsigned char *restrict src, unsigned char *restrict dst, unsigned int width, unsigned int height, const unsigned int size)
|
||
|
|
{
|
||
|
|
for(unsigned int j=0; j < height; j++) {
|
||
|
|
unsigned char *restrict row = src + j*width;
|
||
|
|
|
||
|
|
// accumulate sum for pixels outside line
|
||
|
|
unsigned int sum;
|
||
|
|
sum = row[0]*size;
|
||
|
|
for(unsigned int i=0; i < size; i++) {
|
||
|
|
sum += row[i];
|
||
|
|
}
|
||
|
|
|
||
|
|
// blur with left side outside line
|
||
|
|
for(unsigned int i=0; i < size; i++) {
|
||
|
|
sum -= row[0];
|
||
|
|
sum += row[i+size];
|
||
|
|
|
||
|
|
dst[i*height + j] = sum / (size*2);
|
||
|
|
}
|
||
|
|
|
||
|
|
for(unsigned int i=size; i < width-size; i++) {
|
||
|
|
sum -= row[i-size];
|
||
|
|
sum += row[i+size];
|
||
|
|
|
||
|
|
dst[i*height + j] = sum / (size*2);
|
||
|
|
}
|
||
|
|
|
||
|
|
// blur with right side outside line
|
||
|
|
for(unsigned int i=width-size; i < width; i++) {
|
||
|
|
sum -= row[i-size];
|
||
|
|
sum += row[width-1];
|
||
|
|
|
||
|
|
dst[i*height + j] = sum / (size*2);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Picks maximum of neighboring pixels (blur + lighten)
|
||
|
|
*/
|
||
|
|
LIQ_PRIVATE void liq_max3(unsigned char *src, unsigned char *dst, unsigned int width, unsigned int height)
|
||
|
|
{
|
||
|
|
for(unsigned int j=0; j < height; j++) {
|
||
|
|
const unsigned char *row = src + j*width,
|
||
|
|
*prevrow = src + (j > 1 ? j-1 : 0)*width,
|
||
|
|
*nextrow = src + MIN(height-1,j+1)*width;
|
||
|
|
|
||
|
|
unsigned char prev,curr=row[0],next=row[0];
|
||
|
|
|
||
|
|
for(unsigned int i=0; i < width-1; i++) {
|
||
|
|
prev=curr;
|
||
|
|
curr=next;
|
||
|
|
next=row[i+1];
|
||
|
|
|
||
|
|
unsigned char t1 = MAX(prev,next);
|
||
|
|
unsigned char t2 = MAX(nextrow[i],prevrow[i]);
|
||
|
|
*dst++ = MAX(curr,MAX(t1,t2));
|
||
|
|
}
|
||
|
|
unsigned char t1 = MAX(curr,next);
|
||
|
|
unsigned char t2 = MAX(nextrow[width-1],prevrow[width-1]);
|
||
|
|
*dst++ = MAX(t1,t2);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Picks minimum of neighboring pixels (blur + darken)
|
||
|
|
*/
|
||
|
|
LIQ_PRIVATE void liq_min3(unsigned char *src, unsigned char *dst, unsigned int width, unsigned int height)
|
||
|
|
{
|
||
|
|
for(unsigned int j=0; j < height; j++) {
|
||
|
|
const unsigned char *row = src + j*width,
|
||
|
|
*prevrow = src + (j > 1 ? j-1 : 0)*width,
|
||
|
|
*nextrow = src + MIN(height-1,j+1)*width;
|
||
|
|
|
||
|
|
unsigned char prev,curr=row[0],next=row[0];
|
||
|
|
|
||
|
|
for(unsigned int i=0; i < width-1; i++) {
|
||
|
|
prev=curr;
|
||
|
|
curr=next;
|
||
|
|
next=row[i+1];
|
||
|
|
|
||
|
|
unsigned char t1 = MIN(prev,next);
|
||
|
|
unsigned char t2 = MIN(nextrow[i],prevrow[i]);
|
||
|
|
*dst++ = MIN(curr,MIN(t1,t2));
|
||
|
|
}
|
||
|
|
unsigned char t1 = MIN(curr,next);
|
||
|
|
unsigned char t2 = MIN(nextrow[width-1],prevrow[width-1]);
|
||
|
|
*dst++ = MIN(t1,t2);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
Filters src image and saves it to dst, overwriting tmp in the process.
|
||
|
|
Image must be width*height pixels high. Size controls radius of box blur.
|
||
|
|
*/
|
||
|
|
LIQ_PRIVATE void liq_blur(unsigned char *src, unsigned char *tmp, unsigned char *dst, unsigned int width, unsigned int height, unsigned int size)
|
||
|
|
{
|
||
|
|
assert(size > 0);
|
||
|
|
if (width < 2*size+1 || height < 2*size+1) {
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
transposing_1d_blur(src, tmp, width, height, size);
|
||
|
|
transposing_1d_blur(tmp, dst, height, width, size);
|
||
|
|
}
|