result_t Image::colorClosestAlpha(int32_t red, int32_t green, int32_t blue,
double alpha, int32_t &retVal)
{
if (!m_image)
return CHECK_ERROR(CALL_E_INVALID_CALL);
if (red < 0 || red > 255 || green < 0 || green > 255 || blue < 0
|| blue > 255 || alpha < 0 || alpha > 1)
return CHECK_ERROR(CALL_E_INVALIDARG);
retVal = gdImageColorClosestAlpha(m_image, red, green, blue, doubleToInt(alpha * 127));
return 0;
}
/* This algorithm comes from pnmcrop (http://netpbm.sourceforge.net/)
* Three steps:
* - if 3 corners are equal.
* - if two are equal.
* - Last solution: average the colors
*/
static int gdGuessBackgroundColorFromCorners(gdImagePtr im, int *color)
{
const int tl = gdImageGetPixel(im, 0, 0);
const int tr = gdImageGetPixel(im, gdImageSX(im) - 1, 0);
const int bl = gdImageGetPixel(im, 0, gdImageSY(im) -1);
const int br = gdImageGetPixel(im, gdImageSX(im) - 1, gdImageSY(im) -1);
if (tr == bl && tr == br) {
*color = tr;
return 3;
} else if (tl == bl && tl == br) {
*color = tl;
return 3;
} else if (tl == tr && tl == br) {
*color = tl;
return 3;
} else if (tl == tr && tl == bl) {
*color = tl;
return 3;
} else if (tl == tr || tl == bl || tl == br) {
*color = tl;
return 2;
} else if (tr == bl || tr == br) {
*color = tr;
return 2;
} else if (br == bl) {
*color = bl;
return 2;
} else {
register int r,b,g,a;
r = (int)(0.5f + (gdImageRed(im, tl) + gdImageRed(im, tr) + gdImageRed(im, bl) + gdImageRed(im, br)) / 4);
g = (int)(0.5f + (gdImageGreen(im, tl) + gdImageGreen(im, tr) + gdImageGreen(im, bl) + gdImageGreen(im, br)) / 4);
b = (int)(0.5f + (gdImageBlue(im, tl) + gdImageBlue(im, tr) + gdImageBlue(im, bl) + gdImageBlue(im, br)) / 4);
a = (int)(0.5f + (gdImageAlpha(im, tl) + gdImageAlpha(im, tr) + gdImageAlpha(im, bl) + gdImageAlpha(im, br)) / 4);
*color = gdImageColorClosestAlpha(im, r, g, b, a);
return 0;
}
}
/**
* Function: gdImageCropAuto
*
* Crop an image automatically
*
* This function detects the cropping area according to the given _mode_.
*
* Parameters:
* im - The image.
* mode - The cropping mode, see <gdCropMode>.
*
* Returns:
* The newly created cropped image, or NULL on failure.
*
* See also:
* - <gdImageCrop>
* - <gdImageCropThreshold>
*/
BGD_DECLARE(gdImagePtr) gdImageCropAuto(gdImagePtr im, const unsigned int mode)
{
const int width = gdImageSX(im);
const int height = gdImageSY(im);
int x,y;
int color, match;
gdRect crop;
crop.x = 0;
crop.y = 0;
crop.width = 0;
crop.height = 0;
switch (mode) {
case GD_CROP_TRANSPARENT:
color = gdImageGetTransparent(im);
break;
case GD_CROP_BLACK:
color = gdImageColorClosestAlpha(im, 0, 0, 0, 0);
break;
case GD_CROP_WHITE:
color = gdImageColorClosestAlpha(im, 255, 255, 255, 0);
break;
case GD_CROP_SIDES:
gdGuessBackgroundColorFromCorners(im, &color);
break;
case GD_CROP_DEFAULT:
default:
color = gdImageGetTransparent(im);
break;
}
/* TODO: Add gdImageGetRowPtr and works with ptr at the row level
* for the true color and palette images
* new formats will simply work with ptr
*/
match = 1;
for (y = 0; match && y < height; y++) {
for (x = 0; match && x < width; x++) {
match = (color == gdImageGetPixel(im, x,y));
}
}
/* Whole image would be cropped > bye */
if (match) {
return NULL;
}
crop.y = y - 1;
match = 1;
for (y = height - 1; match && y >= 0; y--) {
for (x = 0; match && x < width; x++) {
match = (color == gdImageGetPixel(im, x,y));
}
}
crop.height = y - crop.y + 2;
match = 1;
for (x = 0; match && x < width; x++) {
for (y = 0; match && y < crop.y + crop.height; y++) {
match = (color == gdImageGetPixel(im, x,y));
}
}
crop.x = x - 1;
match = 1;
for (x = width - 1; match && x >= 0; x--) {
for (y = 0; match && y < crop.y + crop.height; y++) {
match = (color == gdImageGetPixel(im, x,y));
}
}
crop.width = x - crop.x + 2;
return gdImageCrop(im, &crop);
}
/**
* Function: gdImageAutoCrop
* Automatic croping of the src image using the given mode
* (see <gdCropMode>)
*
*
* Parameters:
* im - Source image
* mode - crop mode
*
* Returns:
* <gdImagePtr> on success or NULL
*
* See also:
* <gdCropMode>
*/
gdImagePtr gdImageCropAuto(gdImagePtr im, const unsigned int mode)
{
const int width = gdImageSX(im);
const int height = gdImageSY(im);
int x,y;
int color, corners, match;
gdRect crop;
crop.x = 0;
crop.y = 0;
crop.width = 0;
crop.height = 0;
switch (mode) {
case GD_CROP_TRANSPARENT:
color = gdImageGetTransparent(im);
break;
case GD_CROP_BLACK:
color = gdImageColorClosestAlpha(im, 0, 0, 0, 0);
break;
case GD_CROP_WHITE:
color = gdImageColorClosestAlpha(im, 255, 255, 255, 0);
break;
case GD_CROP_SIDES:
corners = gdGuessBackgroundColorFromCorners(im, &color);
break;
case GD_CROP_DEFAULT:
default:
color = gdImageGetTransparent(im);
if (color == -1) {
corners = gdGuessBackgroundColorFromCorners(im, &color);
}
break;
}
/* TODO: Add gdImageGetRowPtr and works with ptr at the row level
* for the true color and palette images
* new formats will simply work with ptr
*/
match = 1;
for (y = 0; match && y < height; y++) {
for (x = 0; match && x < width; x++) {
int c2 = gdImageGetPixel(im, x, y);
match = (color == c2);
}
}
/* Nothing to do > bye
* Duplicate the image?
*/
if (y == height - 1) {
return NULL;
}
crop.y = y -1;
match = 1;
for (y = height - 1; match && y >= 0; y--) {
for (x = 0; match && x < width; x++) {
match = (color == gdImageGetPixel(im, x,y));
}
}
if (y == 0) {
crop.height = height - crop.y + 1;
} else {
crop.height = y - crop.y + 2;
}
match = 1;
for (x = 0; match && x < width; x++) {
for (y = 0; match && y < crop.y + crop.height - 1; y++) {
match = (color == gdImageGetPixel(im, x,y));
}
}
crop.x = x - 1;
match = 1;
for (x = width - 1; match && x >= 0; x--) {
for (y = 0; match && y < crop.y + crop.height - 1; y++) {
match = (color == gdImageGetPixel(im, x,y));
}
}
crop.width = x - crop.x + 2;
if (crop.x <= 0 || crop.y <= 0 || crop.width <= 0 || crop.height <= 0) {
return NULL;
}
return gdImageCrop(im, &crop);
}