/*!
* pixProjectivePtaGammaXform()
*
* Input: pixs (32 bpp rgb)
* gamma (gamma correction; must be > 0.0)
* ptad (3 pts of final coordinate space)
* ptas (3 pts of initial coordinate space)
* fract (between 0.0 and 1.0, with 1.0 fully transparent)
* border (of pixels to capture transformed source pixels)
* Return: pixd, or null on error
*
* Notes:
* (1) This wraps a gamma/inverse-gamma photometric transform around
* pixProjectivePtaWithAlpha().
* (2) For usage, see notes in pixProjectivePtaWithAlpha() and
* pixGammaTRCWithAlpha().
* (3) The basic idea of a gamma/inverse-gamma transform is to remove
* any gamma correction before the projective transform, and restore
* it afterward. The effects can be subtle, but important for
* some applications. For example, using gamma > 1.0 will
* cause the dark areas to become somewhat lighter and slightly
* reduce aliasing effects when blending using the alpha channel.
*/
PIX *
pixProjectivePtaGammaXform(PIX *pixs,
l_float32 gamma,
PTA *ptad,
PTA *ptas,
l_float32 fract,
l_int32 border)
{
PIX *pixg, *pixd;
PROCNAME("pixProjectivePtaGammaXform");
if (!pixs || (pixGetDepth(pixs) != 32))
return (PIX *)ERROR_PTR("pixs undefined or not 32 bpp", procName, NULL);
if (fract == 0.0)
L_WARNING("fully opaque alpha; image cannot be blended", procName);
if (gamma <= 0.0) {
L_WARNING("gamma must be > 0.0; setting to 1.0", procName);
gamma = 1.0;
}
pixg = pixGammaTRCWithAlpha(NULL, pixs, 1.0 / gamma, 0, 255);
pixd = pixProjectivePtaWithAlpha(pixg, ptad, ptas, NULL, fract, border);
pixGammaTRCWithAlpha(pixd, pixd, gamma, 0, 255);
pixDestroy(&pixg);
return pixd;
}
int main(int argc,
char **argv)
{
PIX *pixs2, *pixs3, *pixb1, *pixb2, *pixb3;
PIX *pixr2, *pixr3;
PIX *pixc1, *pixc2, *pixc3, *pixcs1, *pixcs2, *pixcs3;
PIX *pixd, *pixt1, *pixt2, *pixt3;
PTA *ptas1, *ptas2, *ptas3, *ptad1, *ptad2, *ptad3;
L_REGPARAMS *rp;
if (regTestSetup(argc, argv, &rp))
return 1;
pixc1 = pixRead("test24.jpg");
pixc2 = pixRead("wyom.jpg");
pixc3 = pixRead("marge.jpg");
/* Test alpha blend scaling */
pixd = pixCreate(900, 400, 32);
pixSetAll(pixd);
pixs2 = pixScaleWithAlpha(pixc2, 0.5, 0.5, NULL, 0.3);
pixs3 = pixScaleWithAlpha(pixc3, 0.4, 0.4, NULL, 0.7);
pixb1 = pixBlendWithGrayMask(pixd, pixs3, NULL, 100, 100);
pixb2 = pixBlendWithGrayMask(pixb1, pixs2, NULL, 300, 130);
pixb3 = pixBlendWithGrayMask(pixb2, pixs3, NULL, 600, 160);
regTestWritePixAndCheck(rp, pixb3, IFF_PNG); /* 0 */
pixDisplayWithTitle(pixb3, 900, 100, NULL, rp->display);
pixDestroy(&pixd);
pixDestroy(&pixs2);
pixDestroy(&pixs3);
pixDestroy(&pixb1);
pixDestroy(&pixb2);
pixDestroy(&pixb3);
/* Test alpha blend rotation */
pixd = pixCreate(1200, 800, 32);
pixSetAll(pixd);
pixr3 = pixRotateWithAlpha(pixc3, -0.3, NULL, 1.0);
pixr2 = pixRotateWithAlpha(pixc2, +0.3, NULL, 1.0);
pixb3 = pixBlendWithGrayMask(pixd, pixr3, NULL, 100, 100);
pixb2 = pixBlendWithGrayMask(pixb3, pixr2, NULL, 400, 100);
regTestWritePixAndCheck(rp, pixb2, IFF_PNG); /* 1 */
pixDisplayWithTitle(pixb2, 500, 100, NULL, rp->display);
pixDestroy(&pixd);
pixDestroy(&pixr3);
pixDestroy(&pixr2);
pixDestroy(&pixb3);
pixDestroy(&pixb2);
pixcs1 = pixScale(pixc1, 0.35, 0.35);
pixcs2 = pixScale(pixc2, 0.55, 0.55);
pixcs3 = pixScale(pixc3, 0.65, 0.65);
/* Test alpha blend affine */
pixd = pixCreate(800, 900, 32);
pixSetAll(pixd);
MakePtas(2, 3, &ptas1, &ptad1);
MakePtas(4, 3, &ptas2, &ptad2);
MakePtas(3, 3, &ptas3, &ptad3);
pixt1 = pixAffinePtaWithAlpha(pixcs1, ptad1, ptas1, NULL, 1.0, 300);
pixt2 = pixAffinePtaWithAlpha(pixcs2, ptad2, ptas2, NULL, 0.8, 400);
pixt3 = pixAffinePtaWithAlpha(pixcs3, ptad3, ptas3, NULL, 0.7, 300);
pixb1 = pixBlendWithGrayMask(pixd, pixt1, NULL, -250, 20);
pixb2 = pixBlendWithGrayMask(pixb1, pixt2, NULL, -150, -250);
pixb3 = pixBlendWithGrayMask(pixb2, pixt3, NULL, -100, 220);
regTestWritePixAndCheck(rp, pixb3, IFF_PNG); /* 2 */
pixDisplayWithTitle(pixb3, 100, 100, NULL, rp->display);
pixDestroy(&pixd);
pixDestroy(&pixb1);
pixDestroy(&pixb2);
pixDestroy(&pixb3);
pixDestroy(&pixt1);
pixDestroy(&pixt2);
pixDestroy(&pixt3);
ptaDestroy(&ptas1);
ptaDestroy(&ptas2);
ptaDestroy(&ptas3);
ptaDestroy(&ptad1);
ptaDestroy(&ptad2);
ptaDestroy(&ptad3);
/* Test alpha blend projective */
pixd = pixCreate(900, 900, 32);
pixSetAll(pixd);
MakePtas(2, 4, &ptas1, &ptad1);
MakePtas(4, 4, &ptas2, &ptad2);
MakePtas(3, 4, &ptas3, &ptad3);
pixt1 = pixProjectivePtaWithAlpha(pixcs1, ptad1, ptas1, NULL, 1.0, 300);
pixt2 = pixProjectivePtaWithAlpha(pixcs2, ptad2, ptas2, NULL, 0.8, 400);
pixt3 = pixProjectivePtaWithAlpha(pixcs3, ptad3, ptas3, NULL, 0.7, 400);
pixb1 = pixBlendWithGrayMask(pixd, pixt1, NULL, -150, 20);
pixb2 = pixBlendWithGrayMask(pixb1, pixt2, NULL, -50, -250);
pixb3 = pixBlendWithGrayMask(pixb2, pixt3, NULL, -100, 220);
regTestWritePixAndCheck(rp, pixb3, IFF_PNG); /* 3 */
pixDisplayWithTitle(pixb3, 300, 100, NULL, rp->display);
pixDestroy(&pixd);
pixDestroy(&pixb1);
pixDestroy(&pixb2);
pixDestroy(&pixb3);
pixDestroy(&pixt1);
pixDestroy(&pixt2);
pixDestroy(&pixt3);
ptaDestroy(&ptas1);
ptaDestroy(&ptas2);
ptaDestroy(&ptas3);
ptaDestroy(&ptad1);
ptaDestroy(&ptad2);
ptaDestroy(&ptad3);
/* Test alpha blend bilinear */
pixd = pixCreate(900, 900, 32);
pixSetAll(pixd);
MakePtas(2, 4, &ptas1, &ptad1);
MakePtas(4, 4, &ptas2, &ptad2);
MakePtas(3, 4, &ptas3, &ptad3);
pixt1 = pixBilinearPtaWithAlpha(pixcs1, ptad1, ptas1, NULL, 1.0, 300);
pixt2 = pixBilinearPtaWithAlpha(pixcs2, ptad2, ptas2, NULL, 0.8, 400);
pixt3 = pixBilinearPtaWithAlpha(pixcs3, ptad3, ptas3, NULL, 0.7, 400);
pixb1 = pixBlendWithGrayMask(pixd, pixt1, NULL, -150, 20);
pixb2 = pixBlendWithGrayMask(pixb1, pixt2, NULL, -50, -250);
pixb3 = pixBlendWithGrayMask(pixb2, pixt3, NULL, -100, 220);
regTestWritePixAndCheck(rp, pixb3, IFF_PNG); /* 4 */
pixDisplayWithTitle(pixb3, 500, 100, NULL, rp->display);
pixDestroy(&pixd);
pixDestroy(&pixb1);
pixDestroy(&pixb2);
pixDestroy(&pixb3);
pixDestroy(&pixt1);
pixDestroy(&pixt2);
pixDestroy(&pixt3);
ptaDestroy(&ptas1);
ptaDestroy(&ptas2);
ptaDestroy(&ptas3);
ptaDestroy(&ptad1);
ptaDestroy(&ptad2);
ptaDestroy(&ptad3);
pixDestroy(&pixc1);
pixDestroy(&pixc2);
pixDestroy(&pixc3);
pixDestroy(&pixcs1);
pixDestroy(&pixcs2);
pixDestroy(&pixcs3);
return regTestCleanup(rp);
}
