root/libgd/gd_filter.c

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DEFINITIONS

This source file includes following definitions.
  1. gdImageNegate
  2. gdImageGrayScale
  3. gdImageBrightness
  4. gdImageContrast
  5. gdImageColor
  6. gdImageConvolution
  7. gdImageSelectiveBlur
  8. gdImageEdgeDetectQuick
  9. gdImageGaussianBlur
  10. gdImageEmboss
  11. gdImageMeanRemoval
  12. gdImageSmooth

#if HAVE_GD_BUNDLED
# include "gd.h"
#else
# include <gd.h>
#endif

#include "gd_intern.h"

/* Filters function added on 2003/12
 * by Pierre-Alain Joye (pierre@php.net)
 **/
/* Begin filters function */
#define GET_PIXEL_FUNCTION(src)(src->trueColor?gdImageGetTrueColorPixel:gdImageGetPixel)

/* invert src image */
int gdImageNegate(gdImagePtr src)
{
        int x, y;
        int r,g,b,a;
        int new_pxl, pxl;
        typedef int (*FuncPtr)(gdImagePtr, int, int);
        FuncPtr f;

        if (src==NULL) {
                return 0;
        }

        f = GET_PIXEL_FUNCTION(src);

        for (y=0; y<src->sy; ++y) {
                for (x=0; x<src->sx; ++x) {
                        pxl = f (src, x, y);
                        r = gdImageRed(src, pxl);
                        g = gdImageGreen(src, pxl);
                        b = gdImageBlue(src, pxl);
                        a = gdImageAlpha(src, pxl);

                        new_pxl = gdImageColorAllocateAlpha(src, 255-r, 255-g, 255-b, a);
                        if (new_pxl == -1) {
                                new_pxl = gdImageColorClosestAlpha(src, 255-r, 255-g, 255-b, a);
                        }
                        gdImageSetPixel (src, x, y, new_pxl);
                }
        }
        return 1;
}

/* Convert the image src to a grayscale image */
int gdImageGrayScale(gdImagePtr src)
{
        int x, y;
        int r,g,b,a;
        int new_pxl, pxl;
        typedef int (*FuncPtr)(gdImagePtr, int, int);
        FuncPtr f;
        f = GET_PIXEL_FUNCTION(src);

        if (src==NULL) {
                return 0;
        }

        for (y=0; y<src->sy; ++y) {
                for (x=0; x<src->sx; ++x) {
                        pxl = f (src, x, y);
                        r = gdImageRed(src, pxl);
                        g = gdImageGreen(src, pxl);
                        b = gdImageBlue(src, pxl);
                        a = gdImageAlpha(src, pxl);
                        r = g = b = (int) (.299 * r + .587 * g + .114 * b);

                        new_pxl = gdImageColorAllocateAlpha(src, r, g, b, a);
                        if (new_pxl == -1) {
                                new_pxl = gdImageColorClosestAlpha(src, r, g, b, a);
                        }
                        gdImageSetPixel (src, x, y, new_pxl);
                }
        }
        return 1;
}

/* Set the brightness level <level> for the image src */
int gdImageBrightness(gdImagePtr src, int brightness)
{
        int x, y;
        int r,g,b,a;
        int new_pxl, pxl;
        typedef int (*FuncPtr)(gdImagePtr, int, int);
        FuncPtr f;
        f = GET_PIXEL_FUNCTION(src);

        if (src==NULL || (brightness < -255 || brightness>255)) {
                return 0;
        }

        if (brightness==0) {
                return 1;
        }

        for (y=0; y<src->sy; ++y) {
                for (x=0; x<src->sx; ++x) {
                        pxl = f (src, x, y);

                        r = gdImageRed(src, pxl);
                        g = gdImageGreen(src, pxl);
                        b = gdImageBlue(src, pxl);
                        a = gdImageAlpha(src, pxl);

                        r = r + brightness;
                        g = g + brightness;
                        b = b + brightness;

                        r = (r > 255)? 255 : ((r < 0)? 0:r);
                        g = (g > 255)? 255 : ((g < 0)? 0:g);
                        b = (b > 255)? 255 : ((b < 0)? 0:b);

                        new_pxl = gdImageColorAllocateAlpha(src, (int)r, (int)g, (int)b, a);
                        if (new_pxl == -1) {
                                new_pxl = gdImageColorClosestAlpha(src, (int)r, (int)g, (int)b, a);
                        }
                        gdImageSetPixel (src, x, y, new_pxl);
                }
        }
        return 1;
}


int gdImageContrast(gdImagePtr src, double contrast)
{
        int x, y;
        int r,g,b,a;
        double rf,gf,bf;
        int new_pxl, pxl;
        typedef int (*FuncPtr)(gdImagePtr, int, int);

        FuncPtr f;
        f = GET_PIXEL_FUNCTION(src);

        if (src==NULL) {
                return 0;
        }

        contrast = (double)(100.0-contrast)/100.0;
        contrast = contrast*contrast;

        for (y=0; y<src->sy; ++y) {
                for (x=0; x<src->sx; ++x) {
                        pxl = f(src, x, y);

                        r = gdImageRed(src, pxl);
                        g = gdImageGreen(src, pxl);
                        b = gdImageBlue(src, pxl);
                        a = gdImageAlpha(src, pxl);

                        rf = (double)r/255.0;
                        rf = rf-0.5;
                        rf = rf*contrast;
                        rf = rf+0.5;
                        rf = rf*255.0;

                        bf = (double)b/255.0;
                        bf = bf-0.5;
                        bf = bf*contrast;
                        bf = bf+0.5;
                        bf = bf*255.0;

                        gf = (double)g/255.0;
                        gf = gf-0.5;
                        gf = gf*contrast;
                        gf = gf+0.5;
                        gf = gf*255.0;

                        rf = (rf > 255.0)? 255.0 : ((rf < 0.0)? 0.0:rf);
                        gf = (gf > 255.0)? 255.0 : ((gf < 0.0)? 0.0:gf);
                        bf = (bf > 255.0)? 255.0 : ((bf < 0.0)? 0.0:bf);

                        new_pxl = gdImageColorAllocateAlpha(src, (int)rf, (int)gf, (int)bf, a);
                        if (new_pxl == -1) {
                                new_pxl = gdImageColorClosestAlpha(src, (int)rf, (int)gf, (int)bf, a);
                        }
                        gdImageSetPixel (src, x, y, new_pxl);
                }
        }
        return 1;
}


int gdImageColor(gdImagePtr src, const int red, const int green, const int blue, const int alpha)
{
        int x, y;
        int new_pxl, pxl;
        typedef int (*FuncPtr)(gdImagePtr, int, int);
        FuncPtr f;

        if (src == NULL) {
                return 0;
        }

        f = GET_PIXEL_FUNCTION(src);

        for (y=0; y<src->sy; ++y) {
                for (x=0; x<src->sx; ++x) {
                        int r,g,b,a;

                        pxl = f(src, x, y);
                        r = gdImageRed(src, pxl);
                        g = gdImageGreen(src, pxl);
                        b = gdImageBlue(src, pxl);
                        a = gdImageAlpha(src, pxl);

                        r = r + red;
                        g = g + green;
                        b = b + blue;
                        a = a + alpha;

                        r = (r > 255)? 255 : ((r < 0)? 0 : r);
                        g = (g > 255)? 255 : ((g < 0)? 0 : g);
                        b = (b > 255)? 255 : ((b < 0)? 0 : b);
                        a = (a > 127)? 127 : ((a < 0)? 0 : a);

                        new_pxl = gdImageColorAllocateAlpha(src, r, g, b, a);
                        if (new_pxl == -1) {
                                new_pxl = gdImageColorClosestAlpha(src, r, g, b, a);
                        }
                        gdImageSetPixel (src, x, y, new_pxl);
                }
        }
        return 1;
}

int gdImageConvolution(gdImagePtr src, float filter[3][3], float filter_div, float offset)
{
        int         x, y, i, j, new_a;
        float       new_r, new_g, new_b;
        int         new_pxl, pxl=0;
        gdImagePtr  srcback;
        typedef int (*FuncPtr)(gdImagePtr, int, int);
        FuncPtr f;

        if (src==NULL) {
                return 0;
        }

        /* We need the orinal image with each safe neoghb. pixel */
        srcback = gdImageCreateTrueColor (src->sx, src->sy);
        if (srcback==NULL) {
                return 0;
        }

        gdImageSaveAlpha(srcback, 1);
        new_pxl = gdImageColorAllocateAlpha(srcback, 0, 0, 0, 127);
        gdImageFill(srcback, 0, 0, new_pxl);

        gdImageCopy(srcback, src,0,0,0,0,src->sx,src->sy);

        f = GET_PIXEL_FUNCTION(src);

        for ( y=0; y<src->sy; y++) {
                for(x=0; x<src->sx; x++) {
                        new_r = new_g = new_b = 0;
                        new_a = gdImageAlpha(srcback, pxl);

                        for (j=0; j<3; j++) {
                                int yv = MIN(MAX(y - 1 + j, 0), src->sy - 1);
                                for (i=0; i<3; i++) {
                                        pxl = f(srcback, MIN(MAX(x - 1 + i, 0), src->sx - 1), yv);
                                        new_r += (float)gdImageRed(srcback, pxl) * filter[j][i];
                                        new_g += (float)gdImageGreen(srcback, pxl) * filter[j][i];
                                        new_b += (float)gdImageBlue(srcback, pxl) * filter[j][i];
                                }
                        }

                        new_r = (new_r/filter_div)+offset;
                        new_g = (new_g/filter_div)+offset;
                        new_b = (new_b/filter_div)+offset;

                        new_r = (new_r > 255.0f)? 255.0f : ((new_r < 0.0f)? 0.0f:new_r);
                        new_g = (new_g > 255.0f)? 255.0f : ((new_g < 0.0f)? 0.0f:new_g);
                        new_b = (new_b > 255.0f)? 255.0f : ((new_b < 0.0f)? 0.0f:new_b);

                        new_pxl = gdImageColorAllocateAlpha(src, (int)new_r, (int)new_g, (int)new_b, new_a);
                        if (new_pxl == -1) {
                                new_pxl = gdImageColorClosestAlpha(src, (int)new_r, (int)new_g, (int)new_b, new_a);
                        }
                        gdImageSetPixel (src, x, y, new_pxl);
                }
        }
        gdImageDestroy(srcback);
        return 1;
}

int gdImageSelectiveBlur( gdImagePtr src)
{
        int         x, y, i, j;
        float       new_r, new_g, new_b;
        int         new_pxl, cpxl, pxl, new_a=0;
        float flt_r [3][3];
        float flt_g [3][3];
        float flt_b [3][3];
        float flt_r_sum, flt_g_sum, flt_b_sum;

        gdImagePtr srcback;
        typedef int (*FuncPtr)(gdImagePtr, int, int);
        FuncPtr f;

        if (src==NULL) {
                return 0;
        }

        /* We need the orinal image with each safe neoghb. pixel */
        srcback = gdImageCreateTrueColor (src->sx, src->sy);
        if (srcback==NULL) {
                return 0;
        }
        gdImageCopy(srcback, src,0,0,0,0,src->sx,src->sy);

        f = GET_PIXEL_FUNCTION(src);

        for(y = 0; y<src->sy; y++) {
                for (x=0; x<src->sx; x++) {
                      flt_r_sum = flt_g_sum = flt_b_sum = 0.0;
                        cpxl = f(src, x, y);

                        for (j=0; j<3; j++) {
                                for (i=0; i<3; i++) {
                                        if ((j == 1) && (i == 1)) {
                                                flt_r[1][1] = flt_g[1][1] = flt_b[1][1] = 0.5;
                                        } else {
                                                pxl = f(src, x-(3>>1)+i, y-(3>>1)+j);
                                                new_a = gdImageAlpha(srcback, pxl);

                                                new_r = ((float)gdImageRed(srcback, cpxl)) - ((float)gdImageRed (srcback, pxl));

                                                if (new_r < 0.0f) {
                                                        new_r = -new_r;
                                                }
                                                if (new_r != 0) {
                                                        flt_r[j][i] = 1.0f/new_r;
                                                } else {
                                                        flt_r[j][i] = 1.0f;
                                                }

                                                new_g = ((float)gdImageGreen(srcback, cpxl)) - ((float)gdImageGreen(srcback, pxl));

                                                if (new_g < 0.0f) {
                                                        new_g = -new_g;
                                                }
                                                if (new_g != 0) {
                                                        flt_g[j][i] = 1.0f/new_g;
                                                } else {
                                                        flt_g[j][i] = 1.0f;
                                                }

                                                new_b = ((float)gdImageBlue(srcback, cpxl)) - ((float)gdImageBlue(srcback, pxl));

                                                if (new_b < 0.0f) {
                                                        new_b = -new_b;
                                                }
                                                if (new_b != 0) {
                                                        flt_b[j][i] = 1.0f/new_b;
                                                } else {
                                                        flt_b[j][i] = 1.0f;
                                                }
                                        }

                                        flt_r_sum += flt_r[j][i];
                                        flt_g_sum += flt_g[j][i];
                                        flt_b_sum += flt_b [j][i];
                                }
                        }

                        for (j=0; j<3; j++) {
                                for (i=0; i<3; i++) {
                                        if (flt_r_sum != 0.0) {
                                                flt_r[j][i] /= flt_r_sum;
                                        }
                                        if (flt_g_sum != 0.0) {
                                                flt_g[j][i] /= flt_g_sum;
                                        }
                                        if (flt_b_sum != 0.0) {
                                                flt_b [j][i] /= flt_b_sum;
                                        }
                                }
                        }

                        new_r = new_g = new_b = 0.0;

                        for (j=0; j<3; j++) {
                                for (i=0; i<3; i++) {
                                        pxl = f(src, x-(3>>1)+i, y-(3>>1)+j);
                                        new_r += (float)gdImageRed(srcback, pxl) * flt_r[j][i];
                                        new_g += (float)gdImageGreen(srcback, pxl) * flt_g[j][i];
                                        new_b += (float)gdImageBlue(srcback, pxl) * flt_b[j][i];
                                }
                        }

                        new_r = (new_r > 255.0f)? 255.0f : ((new_r < 0.0f)? 0.0f:new_r);
                        new_g = (new_g > 255.0f)? 255.0f : ((new_g < 0.0f)? 0.0f:new_g);
                        new_b = (new_b > 255.0f)? 255.0f : ((new_b < 0.0f)? 0.0f:new_b);
                        new_pxl = gdImageColorAllocateAlpha(src, (int)new_r, (int)new_g, (int)new_b, new_a);
                        if (new_pxl == -1) {
                                new_pxl = gdImageColorClosestAlpha(src, (int)new_r, (int)new_g, (int)new_b, new_a);
                        }
                        gdImageSetPixel (src, x, y, new_pxl);
                }
        }
        gdImageDestroy(srcback);
        return 1;
}

int gdImageEdgeDetectQuick(gdImagePtr src)
{
        float filter[3][3] =    {{-1.0,0.0,-1.0},
                                {0.0,4.0,0.0},
                                {-1.0,0.0,-1.0}};

        return gdImageConvolution(src, filter, 1, 127);
}

int gdImageGaussianBlur(gdImagePtr im)
{
        float filter[3][3] =    {{1.0,2.0,1.0},
                                {2.0,4.0,2.0},
                                {1.0,2.0,1.0}};

        return gdImageConvolution(im, filter, 16, 0);
}

int gdImageEmboss(gdImagePtr im)
{
/*
        float filter[3][3] =    {{1.0,1.0,1.0},
                                {0.0,0.0,0.0},
                                {-1.0,-1.0,-1.0}};
*/
        float filter[3][3] =    {{ 1.5, 0.0, 0.0},
                                 { 0.0, 0.0, 0.0},
                                 { 0.0, 0.0,-1.5}};

        return gdImageConvolution(im, filter, 1, 127);
}

int gdImageMeanRemoval(gdImagePtr im)
{
        float filter[3][3] =    {{-1.0,-1.0,-1.0},
                                {-1.0,9.0,-1.0},
                                {-1.0,-1.0,-1.0}};

        return gdImageConvolution(im, filter, 1, 0);
}

int gdImageSmooth(gdImagePtr im, float weight)
{
        float filter[3][3] =    {{1.0,1.0,1.0},
                                {1.0,0.0,1.0},
                                {1.0,1.0,1.0}};

        filter[1][1] = weight;

        return gdImageConvolution(im, filter, weight+8, 0);
}
/* End filters function */

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