1 files changed, 369 insertions, 0 deletions
diff --git a/ext/gd/libgd/gd_crop.c b/ext/gd/libgd/gd_crop.c
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+++ b/ext/gd/libgd/gd_crop.c
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+/**
+ * Title: Crop
+ *
+ * A couple of functions to crop images, automatically (auto detection of
+ * the borders color), using a given color (with or without tolerance)
+ * or using a selection.
+ *
+ * The threshold method works relatively well but it can be improved.
+ * Maybe L*a*b* and Delta-E will give better results (and a better
+ * granularity).
+ *
+ * Example:
+ * (start code)
+ *   im2 = gdImageAutoCrop(im, GD_CROP_SIDES);
+ *   if (im2) {
+
+ *   }
+ *   gdImageDestroy(im2);
+ *  (end code)
+ **/
+
+#include <gd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+
+static int gdGuessBackgroundColorFromCorners(gdImagePtr im, int *color);
+static int gdColorMatch(gdImagePtr im, int col1, int col2, float threshold);
+
+/**
+ * Function: gdImageCrop
+ *  Crops the src image using the area defined by the <crop> rectangle.
+ *  The result is returned as a new image.
+ *
+ *
+ * Parameters:
+ * 	src - Source image
+ *  crop - Rectangular region to crop
+ *
+ * Returns:
+ *  <gdImagePtr> on success or NULL
+ */
+gdImagePtr gdImageCrop(gdImagePtr src, const gdRectPtr crop)
+{
+	gdImagePtr dst;
+	int y;
+
+	/* check size */
+	if (crop->width<=0 || crop->height<=0) {
+		return NULL;
+	}
+
+	/* allocate the requested size (could be only partially filled) */
+	if (src->trueColor) {
+		dst = gdImageCreateTrueColor(crop->width, crop->height);
+		gdImageSaveAlpha(dst, 1);
+	} else {
+		dst = gdImageCreate(crop->width, crop->height);
+		gdImagePaletteCopy(dst, src);
+	}
+	if (dst == NULL) {
+		return NULL;
+	}
+	dst->transparent = src->transparent;
+
+	/* check position in the src image */
+	if (crop->x < 0 || crop->x>=src->sx || crop->y<0 || crop->y>=src->sy) {
+		return dst;
+	}
+
+	/* reduce size if needed */
+	if ((src->sx - crop->width) < crop->x) {
+		crop->width = src->sx - crop->x;
+	}
+	if ((src->sy - crop->height) < crop->y) {
+		crop->height = src->sy - crop->y;
+	}
+
+#if 0
+printf("rect->x: %i\nrect->y: %i\nrect->width: %i\nrect->height: %i\n", crop->x, crop->y, crop->width, crop->height);
+#endif
+	y = crop->y;
+	if (src->trueColor) {
+		unsigned int dst_y = 0;
+		while (y < (crop->y + (crop->height - 1))) {
+			/* TODO: replace 4 w/byte per channel||pitch once available */
+			memcpy(dst->tpixels[dst_y++], src->tpixels[y++] + crop->x, crop->width * 4);
+		}
+	} else {
+		int x;
+		for (y = crop->y; y < (crop->y + (crop->height - 1)); y++) {
+			for (x = crop->x; x < (crop->x + (crop->width - 1)); x++) {
+				dst->pixels[y - crop->y][x - crop->x] = src->pixels[y][x];
+			}
+		}
+	}
+	return dst;
+}
+
+/**
+ * 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);
+}
+/*TODOs: Implement DeltaE instead, way better perceptual differences */
+/**
+ * Function: gdImageThresholdCrop
+ *  Crop an image using a given color. The threshold argument defines
+ *  the tolerance to be used while comparing the image color and the
+ *  color to crop. The method used to calculate the color difference
+ *  is based on the color distance in the RGB(a) cube.
+ *
+ *
+ * Parameters:
+ * 	im - Source image
+ *  color - color to crop
+ *  threshold - tolerance (0..100)
+ *
+ * Returns:
+ *  <gdImagePtr> on success or NULL
+ *
+ * See also:
+ *  <gdCropMode>, <gdImageAutoCrop> or <gdImageCrop>
+ */
+gdImagePtr gdImageCropThreshold(gdImagePtr im, const unsigned int color, const float threshold)
+{
+	const int width = gdImageSX(im);
+	const int height = gdImageSY(im);
+
+	int x,y;
+	int match;
+	gdRect crop;
+
+	crop.x = 0;
+	crop.y = 0;
+	crop.width = 0;
+	crop.height = 0;
+
+	/* Pierre: crop everything sounds bad */
+	if (threshold > 1.0) {
+		return NULL;
+	}
+
+	/* 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 = (gdColorMatch(im, color, gdImageGetPixel(im, x,y), threshold)) > 0;
+		}
+	}
+
+	/* Pierre
+	 * 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 = (gdColorMatch(im, color, gdImageGetPixel(im, x, y), threshold)) > 0;
+		}
+	}
+
+	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 = (gdColorMatch(im, color, gdImageGetPixel(im, x,y), threshold)) > 0;
+		}
+	}
+	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 = (gdColorMatch(im, color, gdImageGetPixel(im, x,y), threshold)) > 0;
+		}
+	}
+	crop.width = x - crop.x + 2;
+
+	return gdImageCrop(im, &crop);
+}
+
+/* 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) {
+		*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;
+	}
+}
+
+static int gdColorMatch(gdImagePtr im, int col1, int col2, float threshold)
+{
+	const int dr = gdImageRed(im, col1) - gdImageRed(im, col2);
+	const int dg = gdImageGreen(im, col1) - gdImageGreen(im, col2);
+	const int db = gdImageBlue(im, col1) - gdImageBlue(im, col2);
+	const int da = gdImageAlpha(im, col1) - gdImageAlpha(im, col2);
+	const double dist = sqrt(dr * dr + dg * dg + db * db + da * da);
+	const double dist_perc = sqrt(dist / (255^2 + 255^2 + 255^2));
+	return (dist_perc <= threshold);
+	//return (100.0 * dist / 195075) < threshold;
+}
+
+/*
+ * To be implemented when we have more image formats.
+ * Buffer like gray8 gray16 or rgb8 will require some tweak
+ * and can be done in this function (called from the autocrop
+ * function. (Pierre)
+ */
+#if 0
+static int colors_equal (const int col1, const in col2)
+{
+
+}
+#endif