Pillow/libImaging/BoxBlur.c
2014-10-25 04:28:05 +04:00

288 lines
8.3 KiB
C

#include "Python.h"
#include "Imaging.h"
#define MAX(x, y) (((x) > (y)) ? (x) : (y))
#define MIN(x, y) (((x) < (y)) ? (x) : (y))
typedef UINT8 pixel[4];
void
LineBoxBlur32(pixel *line, UINT32 *lineOut, int lastx, int radius, int edgeA,
int edgeB, UINT32 ww, UINT32 fw)
{
int x;
UINT32 acc[4];
UINT32 bulk[4];
#define MOVE_ACC(acc, substract, add) \
acc[0] += line[add][0] - line[substract][0]; \
acc[1] += line[add][1] - line[substract][1]; \
acc[2] += line[add][2] - line[substract][2]; \
acc[3] += line[add][3] - line[substract][3];
#define ADD_FAR(bulk, acc, left, right) \
bulk[0] = (acc[0] * ww) + (line[left][0] + line[right][0]) * fw; \
bulk[1] = (acc[1] * ww) + (line[left][1] + line[right][1]) * fw; \
bulk[2] = (acc[2] * ww) + (line[left][2] + line[right][2]) * fw; \
bulk[3] = (acc[3] * ww) + (line[left][3] + line[right][3]) * fw;
#define SAVE(acc) \
(UINT8)((acc[0] + (1 << 23)) >> 24) << 0 | (UINT8)((acc[1] + (1 << 23)) >> 24) << 8 | \
(UINT8)((acc[2] + (1 << 23)) >> 24) << 16 | (UINT8)((acc[3] + (1 << 23)) >> 24) << 24
/* Compute acc for -1 pixel (outside of image):
From "-radius-1" to "-1" get first pixel,
then from "0" to "radius-1". */
acc[0] = line[0][0] * (radius + 1);
acc[1] = line[0][1] * (radius + 1);
acc[2] = line[0][2] * (radius + 1);
acc[3] = line[0][3] * (radius + 1);
/* As radius can be bigger than xsize, iterate to edgeA -1. */
for (x = 0; x < edgeA - 1; x++) {
acc[0] += line[x][0];
acc[1] += line[x][1];
acc[2] += line[x][2];
acc[3] += line[x][3];
}
/* Then multiply remainder to last x. */
acc[0] += line[lastx][0] * (radius - edgeA + 1);
acc[1] += line[lastx][1] * (radius - edgeA + 1);
acc[2] += line[lastx][2] * (radius - edgeA + 1);
acc[3] += line[lastx][3] * (radius - edgeA + 1);
if (edgeA <= edgeB)
{
/* Substract pixel from left ("0").
Add pixels from radius. */
for (x = 0; x < edgeA; x++) {
MOVE_ACC(acc, 0, x + radius);
ADD_FAR(bulk, acc, 0, x + radius + 1);
lineOut[x] = SAVE(bulk);
}
/* Substract previous pixel from "-radius".
Add pixels from radius. */
for (x = edgeA; x < edgeB; x++) {
MOVE_ACC(acc, x - radius - 1, x + radius);
ADD_FAR(bulk, acc, x - radius - 1, x + radius + 1);
lineOut[x] = SAVE(bulk);
}
/* Substract previous pixel from "-radius".
Add last pixel. */
for (x = edgeB; x <= lastx; x++) {
MOVE_ACC(acc, x - radius - 1, lastx);
ADD_FAR(bulk, acc, x - radius - 1, lastx);
lineOut[x] = SAVE(bulk);
}
}
else
{
for (x = 0; x < edgeB; x++) {
MOVE_ACC(acc, 0, x + radius);
ADD_FAR(bulk, acc, 0, x + radius + 1);
lineOut[x] = SAVE(bulk);
}
for (x = edgeB; x < edgeA; x++) {
MOVE_ACC(acc, 0, lastx);
ADD_FAR(bulk, acc, 0, lastx);
lineOut[x] = SAVE(bulk);
}
for (x = edgeA; x <= lastx; x++) {
MOVE_ACC(acc, x - radius - 1, lastx);
ADD_FAR(bulk, acc, x - radius - 1, lastx);
lineOut[x] = SAVE(bulk);
}
}
#undef MOVE_ACC
#undef ADD_FAR
#undef SAVE
}
void
LineBoxBlur8(UINT8 *line, UINT8 *lineOut, int lastx, int radius, int edgeA,
int edgeB, UINT32 ww, UINT32 fw)
{
int x;
UINT32 acc;
UINT32 bulk;
#define MOVE_ACC(acc, substract, add) \
acc += line[add] - line[substract];
#define ADD_FAR(bulk, acc, left, right) \
bulk = (acc * ww) + (line[left] + line[right]) * fw;
#define SAVE(acc) \
(UINT8)((acc + (1 << 23)) >> 24)
acc = line[0] * (radius + 1);
for (x = 0; x < edgeA - 1; x++) {
acc += line[x];
}
acc += line[lastx] * (radius - edgeA + 1);
if (edgeA <= edgeB)
{
for (x = 0; x < edgeA; x++) {
MOVE_ACC(acc, 0, x + radius);
ADD_FAR(bulk, acc, 0, x + radius + 1);
lineOut[x] = SAVE(bulk);
}
for (x = edgeA; x < edgeB; x++) {
MOVE_ACC(acc, x - radius - 1, x + radius);
ADD_FAR(bulk, acc, x - radius - 1, x + radius + 1);
lineOut[x] = SAVE(bulk);
}
for (x = edgeB; x <= lastx; x++) {
MOVE_ACC(acc, x - radius - 1, lastx);
ADD_FAR(bulk, acc, x - radius - 1, lastx);
lineOut[x] = SAVE(bulk);
}
}
else
{
for (x = 0; x < edgeB; x++) {
MOVE_ACC(acc, 0, x + radius);
ADD_FAR(bulk, acc, 0, x + radius + 1);
lineOut[x] = SAVE(bulk);
}
for (x = edgeB; x < edgeA; x++) {
MOVE_ACC(acc, 0, lastx);
ADD_FAR(bulk, acc, 0, lastx);
lineOut[x] = SAVE(bulk);
}
for (x = edgeA; x <= lastx; x++) {
MOVE_ACC(acc, x - radius - 1, lastx);
ADD_FAR(bulk, acc, x - radius - 1, lastx);
lineOut[x] = SAVE(bulk);
}
}
#undef MOVE_ACC
#undef ADD_FAR
#undef SAVE
}
Imaging
HorizontalBoxBlur(Imaging im, Imaging imOut, float floatRadius)
{
ImagingSectionCookie cookie;
int y;
int radius = (int) floatRadius;
UINT32 ww = (UINT32) (1 << 24) / (floatRadius * 2 + 1);
UINT32 fw = ((1 << 24) - (radius * 2 + 1) * ww) / 2;
int edgeA = MIN(radius + 1, im->xsize);
int edgeB = MAX(im->xsize - radius - 1, 0);
UINT32 *lineOut = calloc(im->xsize, sizeof(UINT32));
if (lineOut == NULL)
return ImagingError_MemoryError();
// printf(">>> %d %d %d\n", radius, ww, fw);
ImagingSectionEnter(&cookie);
if (im->image8)
{
for (y = 0; y < im->ysize; y++) {
LineBoxBlur8(
im->image8[y],
(im == imOut ? (UINT8 *) lineOut : imOut->image8[y]),
im->xsize - 1,
radius, edgeA, edgeB,
ww, fw
);
if (im == imOut) {
// Commit.
memcpy(imOut->image8[y], lineOut, im->xsize);
}
}
}
else
{
for (y = 0; y < im->ysize; y++) {
LineBoxBlur32(
(pixel *) im->image32[y],
im == imOut ? lineOut : (UINT32 *) imOut->image32[y],
im->xsize - 1,
radius, edgeA, edgeB,
ww, fw
);
if (im == imOut) {
// Commit.
memcpy(imOut->image32[y], lineOut, im->xsize * 4);
}
}
}
ImagingSectionLeave(&cookie);
free(lineOut);
return imOut;
}
Imaging
ImagingBoxBlur(Imaging imOut, Imaging imIn, float radius, int n)
{
int i;
if (n < 1) {
return ImagingError_ValueError(
"number of passes must be greater than zero"
);
}
if (strcmp(imIn->mode, imOut->mode) ||
imIn->type != imOut->type ||
imIn->bands != imOut->bands ||
imIn->xsize != imOut->xsize ||
imIn->ysize != imOut->ysize)
return ImagingError_Mismatch();
if (imIn->type != IMAGING_TYPE_UINT8)
return ImagingError_ModeError();
if ( ! (strcmp(imIn->mode, "RGB") == 0 ||
strcmp(imIn->mode, "RGBA") == 0 ||
strcmp(imIn->mode, "RGBX") == 0 ||
strcmp(imIn->mode, "CMYK") == 0 ||
strcmp(imIn->mode, "L") == 0 ||
strcmp(imIn->mode, "LA") == 0))
return ImagingError_ModeError();
/* Create transposed temp image (imIn->ysize x imIn->xsize). */
Imaging temp = ImagingNew(imIn->mode, imIn->ysize, imIn->xsize);
if ( ! temp)
return NULL;
/* Apply one-dimensional blur.
HorizontalBoxBlur transposes image at same time. */
HorizontalBoxBlur(imIn, imOut, radius);
for (i = 1; i < n; i ++) {
HorizontalBoxBlur(imOut, imOut, radius);
}
ImagingTranspose(temp, imOut);
/* Blur transposed result from previout step in same direction.
Reseult will be transposed again. We'll get original image
blurred in both directions. */
for (i = 0; i < n; i ++) {
HorizontalBoxBlur(temp, temp, radius);
}
ImagingTranspose(imOut, temp);
ImagingDelete(temp);
return imOut;
}