root/gd/libgd/gd_rotate.c

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DEFINITIONS

This source file includes following definitions.
  1. gdImageSkewX
  2. gdImageSkewY
  3. gdImageRotate90
  4. gdImageRotate180
  5. gdImageRotate270
  6. gdImageRotate45
  7. gdImageRotate

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

#include "gd_intern.h"
#include <math.h>

/*
 * Rotate function Added on 2003/12
 * by Pierre-Alain Joye (pierre@php.net)
 **/
/* Begin rotate function */
#ifdef ROTATE_PI
#undef ROTATE_PI
#endif /* ROTATE_PI */

#define ROTATE_DEG2RAD  3.1415926535897932384626433832795/180
void gdImageSkewX (gdImagePtr dst, gdImagePtr src, int uRow, int iOffset, double dWeight, int clrBack, int ignoretransparent)
{
        typedef int (*FuncPtr)(gdImagePtr, int, int);
        int i, r, g, b, a, clrBackR, clrBackG, clrBackB, clrBackA;
        FuncPtr f;

        int pxlOldLeft, pxlLeft=0, pxlSrc;

        /* Keep clrBack as color index if required */
        if (src->trueColor) {
                pxlOldLeft = clrBack;
                f = gdImageGetTrueColorPixel;
        } else {
                pxlOldLeft = clrBack;
                clrBackR = gdImageRed(src, clrBack);
                clrBackG = gdImageGreen(src, clrBack);
                clrBackB = gdImageBlue(src, clrBack);
                clrBackA = gdImageAlpha(src, clrBack);
                clrBack =  gdTrueColorAlpha(clrBackR, clrBackG, clrBackB, clrBackA);
                f = gdImageGetPixel;
        }

        for (i = 0; i < iOffset; i++) {
                gdImageSetPixel (dst, i, uRow, clrBack);
        }

        if (i < dst->sx) {
                gdImageSetPixel (dst, i, uRow, clrBack);
        }

        for (i = 0; i < src->sx; i++) {
                pxlSrc = f (src,i,uRow);

                r = (int)(gdImageRed(src,pxlSrc) * dWeight);
                g = (int)(gdImageGreen(src,pxlSrc) * dWeight);
                b = (int)(gdImageBlue(src,pxlSrc) * dWeight);
                a = (int)(gdImageAlpha(src,pxlSrc) * dWeight);

                pxlLeft = gdImageColorAllocateAlpha(src, r, g, b, a);

                if (pxlLeft == -1) {
                        pxlLeft = gdImageColorClosestAlpha(src, r, g, b, a);
                }

                r = gdImageRed(src,pxlSrc) - (gdImageRed(src,pxlLeft) - gdImageRed(src,pxlOldLeft));
                g = gdImageGreen(src,pxlSrc) - (gdImageGreen(src,pxlLeft) - gdImageGreen(src,pxlOldLeft));
                b = gdImageBlue(src,pxlSrc) - (gdImageBlue(src,pxlLeft) - gdImageBlue(src,pxlOldLeft));
                a = gdImageAlpha(src,pxlSrc) - (gdImageAlpha(src,pxlLeft) - gdImageAlpha(src,pxlOldLeft));

        if (r>255) {
                r = 255;
        }

                if (g>255) {
                        g = 255;
                }

                if (b>255) {
                        b = 255;
                }

                if (a>127) {
                        a = 127;
                }

                if (ignoretransparent && pxlSrc == dst->transparent) {
                        pxlSrc = dst->transparent;
                } else {
                        pxlSrc = gdImageColorAllocateAlpha(dst, r, g, b, a);

                        if (pxlSrc == -1) {
                                pxlSrc = gdImageColorClosestAlpha(dst, r, g, b, a);
                        }
                }

                if ((i + iOffset >= 0) && (i + iOffset < dst->sx)) {
                        gdImageSetPixel (dst, i+iOffset, uRow,  pxlSrc);
                }

                pxlOldLeft = pxlLeft;
        }

        i += iOffset;

        if (i < dst->sx) {
                gdImageSetPixel (dst, i, uRow, pxlLeft);
        }

        gdImageSetPixel (dst, iOffset, uRow, clrBack);

        i--;

        while (++i < dst->sx) {
                gdImageSetPixel (dst, i, uRow, clrBack);
        }
}

void gdImageSkewY (gdImagePtr dst, gdImagePtr src, int uCol, int iOffset, double dWeight, int clrBack, int ignoretransparent)
{
        typedef int (*FuncPtr)(gdImagePtr, int, int);
        int i, iYPos=0, r, g, b, a;
        FuncPtr f;
        int pxlOldLeft, pxlLeft=0, pxlSrc;

        if (src->trueColor) {
                f = gdImageGetTrueColorPixel;
        } else {
                f = gdImageGetPixel;
        }

        for (i = 0; i<=iOffset; i++) {
                gdImageSetPixel (dst, uCol, i, clrBack);
        }
        r = (int)((double)gdImageRed(src,clrBack) * dWeight);
        g = (int)((double)gdImageGreen(src,clrBack) * dWeight);
        b = (int)((double)gdImageBlue(src,clrBack) * dWeight);
        a = (int)((double)gdImageAlpha(src,clrBack) * dWeight);

        pxlOldLeft = gdImageColorAllocateAlpha(dst, r, g, b, a);

        for (i = 0; i < src->sy; i++) {
                pxlSrc = f (src, uCol, i);
                iYPos = i + iOffset;

                r = (int)((double)gdImageRed(src,pxlSrc) * dWeight);
                g = (int)((double)gdImageGreen(src,pxlSrc) * dWeight);
                b = (int)((double)gdImageBlue(src,pxlSrc) * dWeight);
                a = (int)((double)gdImageAlpha(src,pxlSrc) * dWeight);

                pxlLeft = gdImageColorAllocateAlpha(src, r, g, b, a);

                if (pxlLeft == -1) {
                        pxlLeft = gdImageColorClosestAlpha(src, r, g, b, a);
                }

                r = gdImageRed(src,pxlSrc) - (gdImageRed(src,pxlLeft) - gdImageRed(src,pxlOldLeft));
                g = gdImageGreen(src,pxlSrc) - (gdImageGreen(src,pxlLeft) - gdImageGreen(src,pxlOldLeft));
                b = gdImageBlue(src,pxlSrc) - (gdImageBlue(src,pxlLeft) - gdImageBlue(src,pxlOldLeft));
                a = gdImageAlpha(src,pxlSrc) - (gdImageAlpha(src,pxlLeft) - gdImageAlpha(src,pxlOldLeft));

                if (r>255) {
                        r = 255;
                }

                if (g>255) {
                        g = 255;
                }

                if (b>255) {
                        b = 255;
                }

                if (a>127) {
                        a = 127;
                }

                if (ignoretransparent && pxlSrc == dst->transparent) {
                        pxlSrc = dst->transparent;
                } else {
                        pxlSrc = gdImageColorAllocateAlpha(dst, r, g, b, a);

                        if (pxlSrc == -1) {
                                pxlSrc = gdImageColorClosestAlpha(dst, r, g, b, a);
                        }
                }

                if ((iYPos >= 0) && (iYPos < dst->sy)) {
                        gdImageSetPixel (dst, uCol, iYPos, pxlSrc);
                }

                pxlOldLeft = pxlLeft;
        }

        i = iYPos;
        if (i < dst->sy) {
                gdImageSetPixel (dst, uCol, i, pxlLeft);
        }

        i--;
        while (++i < dst->sy) {
                gdImageSetPixel (dst, uCol, i, clrBack);
        }
}

/* Rotates an image by 90 degrees (counter clockwise) */
gdImagePtr gdImageRotate90 (gdImagePtr src, int ignoretransparent)
{
        int uY, uX;
        int c,r,g,b,a;
        gdImagePtr dst;
        typedef int (*FuncPtr)(gdImagePtr, int, int);
        FuncPtr f;

        if (src->trueColor) {
                f = gdImageGetTrueColorPixel;
        } else {
                f = gdImageGetPixel;
        }
        dst = gdImageCreateTrueColor(src->sy, src->sx);
        dst->transparent = src->transparent;

        if (dst != NULL) {
                int old_blendmode = dst->alphaBlendingFlag;
                dst->alphaBlendingFlag = 0;

                gdImagePaletteCopy (dst, src);

                for (uY = 0; uY<src->sy; uY++) {
                        for (uX = 0; uX<src->sx; uX++) {
                                c = f (src, uX, uY);
                                if (!src->trueColor) {
                                        r = gdImageRed(src,c);
                                        g = gdImageGreen(src,c);
                                        b = gdImageBlue(src,c);
                                        a = gdImageAlpha(src,c);
                                        c = gdTrueColorAlpha(r, g, b, a);
                                }
                                if (ignoretransparent && c == dst->transparent) {
                                        gdImageSetPixel(dst, uY, (dst->sy - uX - 1), dst->transparent);
                                } else {
                                        gdImageSetPixel(dst, uY, (dst->sy - uX - 1), c);
                                }
                        }
                }
                dst->alphaBlendingFlag = old_blendmode;
        }

        return dst;
}

/* Rotates an image by 180 degrees (counter clockwise) */
gdImagePtr gdImageRotate180 (gdImagePtr src, int ignoretransparent)
{
        int uY, uX;
        int c,r,g,b,a;
        gdImagePtr dst;
        typedef int (*FuncPtr)(gdImagePtr, int, int);
        FuncPtr f;

        if (src->trueColor) {
                f = gdImageGetTrueColorPixel;
        } else {
                f = gdImageGetPixel;
        }
        dst = gdImageCreateTrueColor(src->sx, src->sy);
        dst->transparent = src->transparent;

        if (dst != NULL) {
                int old_blendmode = dst->alphaBlendingFlag;
                dst->alphaBlendingFlag = 0;

                gdImagePaletteCopy (dst, src);

                for (uY = 0; uY<src->sy; uY++) {
                        for (uX = 0; uX<src->sx; uX++) {
                                c = f (src, uX, uY);
                                if (!src->trueColor) {
                                        r = gdImageRed(src,c);
                                        g = gdImageGreen(src,c);
                                        b = gdImageBlue(src,c);
                                        a = gdImageAlpha(src,c);
                                        c = gdTrueColorAlpha(r, g, b, a);
                                }

                                if (ignoretransparent && c == dst->transparent) {
                                        gdImageSetPixel(dst, (dst->sx - uX - 1), (dst->sy - uY - 1), dst->transparent);
                                } else {
                                        gdImageSetPixel(dst, (dst->sx - uX - 1), (dst->sy - uY - 1), c);
                                }
                        }
                }
                dst->alphaBlendingFlag = old_blendmode;
        }

        return dst;
}

/* Rotates an image by 270 degrees (counter clockwise) */
gdImagePtr gdImageRotate270 (gdImagePtr src, int ignoretransparent)
{
        int uY, uX;
        int c,r,g,b,a;
        gdImagePtr dst;
        typedef int (*FuncPtr)(gdImagePtr, int, int);
        FuncPtr f;

        if (src->trueColor) {
                f = gdImageGetTrueColorPixel;
        } else {
                f = gdImageGetPixel;
        }
        dst = gdImageCreateTrueColor (src->sy, src->sx);
        dst->transparent = src->transparent;

        if (dst != NULL) {
                int old_blendmode = dst->alphaBlendingFlag;
                dst->alphaBlendingFlag = 0;

                gdImagePaletteCopy (dst, src);

                for (uY = 0; uY<src->sy; uY++) {
                        for (uX = 0; uX<src->sx; uX++) {
                                c = f (src, uX, uY);
                                if (!src->trueColor) {
                                        r = gdImageRed(src,c);
                                        g = gdImageGreen(src,c);
                                        b = gdImageBlue(src,c);
                                        a = gdImageAlpha(src,c);
                                        c = gdTrueColorAlpha(r, g, b, a);
                                }

                                if (ignoretransparent && c == dst->transparent) {
                                        gdImageSetPixel(dst, (dst->sx - uY - 1), uX, dst->transparent);
                                } else {
                                        gdImageSetPixel(dst, (dst->sx - uY - 1), uX, c);
                                }
                        }
                }
                dst->alphaBlendingFlag = old_blendmode;
        }

        return dst;
}

gdImagePtr gdImageRotate45 (gdImagePtr src, double dAngle, int clrBack, int ignoretransparent)
{
        typedef int (*FuncPtr)(gdImagePtr, int, int);
        gdImagePtr dst1,dst2,dst3;
        FuncPtr f;
        double dRadAngle, dSinE, dTan, dShear;
        double dOffset;     /* Variable skew offset */
        int u, iShear, newx, newy;
        int clrBackR, clrBackG, clrBackB, clrBackA;

        /* See GEMS I for the algorithm details */
        dRadAngle = dAngle * ROTATE_DEG2RAD; /* Angle in radians */
        dSinE = sin (dRadAngle);
        dTan = tan (dRadAngle / 2.0);

        newx = (int)(src->sx + src->sy * fabs(dTan));
        newy = src->sy;

        /* 1st shear */
        if (src->trueColor) {
                f = gdImageGetTrueColorPixel;
        } else {
                f = gdImageGetPixel;
        }

        dst1 = gdImageCreateTrueColor(newx, newy);
        /******* Perform 1st shear (horizontal) ******/
        if (dst1 == NULL) {
                return NULL;
        }
#ifdef HAVE_GD_BUNDLED
        dst1->alphaBlendingFlag = gdEffectReplace;
#else
        gdImageAlphaBlending(dst1, 0);
#endif
        if (dAngle == 0.0) {
                /* Returns copy of src */
                gdImageCopy (dst1, src,0,0,0,0,src->sx,src->sy);
                return dst1;
        }

        gdImagePaletteCopy (dst1, src);

        if (ignoretransparent) {
                if (gdImageTrueColor(src)) {
                        dst1->transparent = src->transparent;
                } else {

                        dst1->transparent = gdTrueColorAlpha(gdImageRed(src, src->transparent), gdImageBlue(src, src->transparent), gdImageGreen(src, src->transparent), 127);
                }
        }

        dRadAngle = dAngle * ROTATE_DEG2RAD; /* Angle in radians */
        dSinE = sin (dRadAngle);
        dTan = tan (dRadAngle / 2.0);

        for (u = 0; u < dst1->sy; u++) {
                if (dTan >= 0.0) {
                        dShear = ((double)(u + 0.5)) * dTan;
                } else {
                        dShear = ((double)(u - dst1->sy) + 0.5) * dTan;
                }

                iShear = (int)floor(dShear);
                gdImageSkewX(dst1, src, u, iShear, (dShear - iShear), clrBack, ignoretransparent);
        }

        /*
        The 1st shear may use the original clrBack as color index
        Convert it once here
        */
        if(!src->trueColor) {
                clrBackR = gdImageRed(src, clrBack);
                clrBackG = gdImageGreen(src, clrBack);
                clrBackB = gdImageBlue(src, clrBack);
                clrBackA = gdImageAlpha(src, clrBack);
                clrBack =  gdTrueColorAlpha(clrBackR, clrBackG, clrBackB, clrBackA);
        }
        /* 2nd shear */
        newx = dst1->sx;

        if (dSinE > 0.0) {
                dOffset = (src->sx-1) * dSinE;
        } else {
                dOffset = -dSinE *  (src->sx - newx);
        }

        newy = (int) ((double) src->sx * fabs( dSinE ) + (double) src->sy * cos (dRadAngle))+1;

        if (src->trueColor) {
                f = gdImageGetTrueColorPixel;
        } else {
                f = gdImageGetPixel;
        }
        dst2 = gdImageCreateTrueColor(newx, newy);
        if (dst2 == NULL) {
                gdImageDestroy(dst1);
                return NULL;
        }

#ifdef HAVE_GD_BUNDLED
        dst2->alphaBlendingFlag = gdEffectReplace;
#else
        gdImageAlphaBlending(dst2, 0);
#endif

        if (ignoretransparent) {
                dst2->transparent = dst1->transparent;
        }

        for (u = 0; u < dst2->sx; u++, dOffset -= dSinE) {
                iShear = (int)floor (dOffset);
                gdImageSkewY(dst2, dst1, u, iShear, (dOffset - (double)iShear), clrBack, ignoretransparent);
        }

        /* 3rd shear */
        gdImageDestroy(dst1);

        newx = (int) ((double)src->sy * fabs (dSinE) + (double)src->sx * cos (dRadAngle)) + 1;
        newy = dst2->sy;

        if (src->trueColor) {
                f = gdImageGetTrueColorPixel;
        } else {
                f = gdImageGetPixel;
        }
        dst3 = gdImageCreateTrueColor(newx, newy);
        if (dst3 == NULL) {
                gdImageDestroy(dst2);
                return NULL;
        }

#ifdef HAVE_GD_BUNDLED
        dst3->alphaBlendingFlag = gdEffectReplace;
#else
        gdImageAlphaBlending(dst3, 0);
#endif

        if (ignoretransparent) {
                dst3->transparent = dst2->transparent;
        }

        if (dSinE >= 0.0) {
                dOffset = (double)(src->sx - 1) * dSinE * -dTan;
        } else {
                dOffset = dTan * ((double)(src->sx - 1) * -dSinE + (double)(1 - newy));
        }

        for (u = 0; u < dst3->sy; u++, dOffset += dTan) {
                int iShear = (int)floor(dOffset);
                gdImageSkewX(dst3, dst2, u, iShear, (dOffset - iShear), clrBack, ignoretransparent);
        }

        gdImageDestroy(dst2);

        return dst3;
}

gdImagePtr gdImageRotate (gdImagePtr src, double dAngle, int clrBack, int ignoretransparent)
{
        gdImagePtr pMidImg;
        gdImagePtr rotatedImg;

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

        if (!gdImageTrueColor(src) && (clrBack < 0 || clrBack>=gdImageColorsTotal(src))) {
                return NULL;
        }

        while (dAngle >= 360.0) {
                dAngle -= 360.0;
        }

        while (dAngle < 0) {
                dAngle += 360.0;
        }

        if (dAngle == 90.00) {
                return gdImageRotate90(src, ignoretransparent);
        }
        if (dAngle == 180.00) {
                return gdImageRotate180(src, ignoretransparent);
        }
        if(dAngle == 270.00) {
                return gdImageRotate270 (src, ignoretransparent);
        }

        if ((dAngle > 45.0) && (dAngle <= 135.0)) {
                pMidImg = gdImageRotate90 (src, ignoretransparent);
                dAngle -= 90.0;
        } else if ((dAngle > 135.0) && (dAngle <= 225.0)) {
                pMidImg = gdImageRotate180 (src, ignoretransparent);
                dAngle -= 180.0;
        } else if ((dAngle > 225.0) && (dAngle <= 315.0)) {
                pMidImg = gdImageRotate270 (src, ignoretransparent);
                dAngle -= 270.0;
        } else {
                return gdImageRotate45 (src, dAngle, clrBack, ignoretransparent);
        }

        if (pMidImg == NULL) {
                return NULL;
        }

        rotatedImg = gdImageRotate45 (pMidImg, dAngle, clrBack, ignoretransparent);
        gdImageDestroy(pMidImg);

        return rotatedImg;
}
/* End Rotate function */



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