void SkTMaskGamma_build_correcting_lut(uint8_t table[256], U8CPU srcI, SkScalar contrast, const SkColorSpaceLuminance& srcConvert, SkScalar srcGamma, const SkColorSpaceLuminance& dstConvert, SkScalar dstGamma) { const float src = (float)srcI / 255.0f; const float linSrc = srcConvert.toLuma(srcGamma, src); //Guess at the dst. The perceptual inverse provides smaller visual //discontinuities when slight changes to desaturated colors cause a channel //to map to a different correcting lut with neighboring srcI. //See https://code.google.com/p/chromium/issues/detail?id=141425#c59 . const float dst = 1.0f - src; const float linDst = dstConvert.toLuma(dstGamma, dst); //Contrast value tapers off to 0 as the src luminance becomes white const float adjustedContrast = SkScalarToFloat(contrast) * linDst; //Remove discontinuity and instability when src is close to dst. //The value 1/256 is arbitrary and appears to contain the instability. if (fabs(src - dst) < (1.0f / 256.0f)) { float ii = 0.0f; for (int i = 0; i < 256; ++i, ii += 1.0f) { float rawSrca = ii / 255.0f; float srca = apply_contrast(rawSrca, adjustedContrast); table[i] = SkToU8(sk_float_round2int(255.0f * srca)); } } else { // Avoid slow int to float conversion. float ii = 0.0f; for (int i = 0; i < 256; ++i, ii += 1.0f) { // 'rawSrca += 1.0f / 255.0f' and even // 'rawSrca = i * (1.0f / 255.0f)' can add up to more than 1.0f. // When this happens the table[255] == 0x0 instead of 0xff. // See http://code.google.com/p/chromium/issues/detail?id=146466 float rawSrca = ii / 255.0f; float srca = apply_contrast(rawSrca, adjustedContrast); SkASSERT(srca <= 1.0f); float dsta = 1.0f - srca; //Calculate the output we want. float linOut = (linSrc * srca + dsta * linDst); SkASSERT(linOut <= 1.0f); float out = dstConvert.fromLuma(dstGamma, linOut); //Undo what the blit blend will do. float result = (out - dst) / (src - dst); SkASSERT(sk_float_round2int(255.0f * result) <= 255); table[i] = SkToU8(sk_float_round2int(255.0f * result)); } } }
unsigned int filter_color(unsigned int color, t_opt *opt) { if (opt->filter == 1) color = filter_sepia(color); if (opt->filter == 2) color = filter_grey(color); if (opt->gamma != -1) color = gamma_filter(color, opt->gamma); if (opt->filter == 3) color = revers_filter(color, opt); if (opt->contrast != 1.0) color = apply_contrast(color, opt); if (opt->saturation != 1.0) color = saturation(color, opt->saturation); return (color); }
int main( int argc , char ** argv ) { printf( "Starting up VoidEye test.\n" ); init_test( "" ); update_texture(); remove_colours(); update_texture(); int b , d , a; b = find_brightest(); d = find_darkest(); a = find_avarage(); printf( "b: %d d: %d a: %d\n", b , d , a ); apply_contrast( 256 ); update_texture(); create_groups(); return 0; }