diff options
| -rw-r--r-- | sent.c | 73 |
1 files changed, 56 insertions, 17 deletions
@@ -282,27 +282,66 @@ ffprepare(Image *img) img->state |= SCALED; } +static unsigned char double_to_uchar_clamp255(double dbl) +{ + dbl = round(dbl); + + return + (dbl < 0.0) ? 0 : + (dbl > 255.0) ? 255 : (unsigned char)dbl; +} + +static int int_clamp(int integer, int lower, int upper) +{ + if (integer < lower) + return lower; + else if (integer >= upper) + return upper - 1; + else + return integer; +} + void ffscale(Image *img) { - unsigned int x, y; - unsigned int width = img->ximg->width; - unsigned int height = img->ximg->height; - char* newBuf = img->ximg->data; - unsigned char* ibuf; - unsigned int jdy = img->ximg->bytes_per_line / 4 - width; - unsigned int dx = (img->bufwidth << 10) / width; - - for (y = 0; y < height; y++) { - unsigned int bufx = img->bufwidth / width; - ibuf = &img->buf[y * img->bufheight / height * img->bufwidth * 3]; - - for (x = 0; x < width; x++) { - *newBuf++ = (ibuf[(bufx >> 10)*3+2]); - *newBuf++ = (ibuf[(bufx >> 10)*3+1]); - *newBuf++ = (ibuf[(bufx >> 10)*3+0]); + const unsigned width = img->ximg->width; + const unsigned height = img->ximg->height; + unsigned char* newBuf = (unsigned char*)img->ximg->data; + const unsigned jdy = img->ximg->bytes_per_line / 4 - width; + + const double x_scale = ((double)img->bufwidth/(double)width); + const double y_scale = ((double)img->bufheight/(double)height); + + for (unsigned y = 0; y < height; ++y) { + const double old_y = (double)y * y_scale; + const double y_factor = ceil(old_y) - old_y; + const int old_y_int_0 = int_clamp((int)floor(old_y), 0, img->bufheight); + const int old_y_int_1 = int_clamp((int)ceil(old_y), 0, img->bufheight); + + for (unsigned x = 0; x < width; ++x) { + const double old_x = (double)x * x_scale; + const double x_factor = ceil(old_x) - old_x; + const int old_x_int_0 = int_clamp((int)floor(old_x), 0, img->bufwidth); + const int old_x_int_1 = int_clamp((int)ceil(old_x), 0, img->bufwidth); + + const unsigned c00_pos = 3*((old_x_int_0) + ((old_y_int_0)*img->bufwidth)); + const unsigned c01_pos = 3*((old_x_int_0) + ((old_y_int_1)*img->bufwidth)); + const unsigned c10_pos = 3*((old_x_int_1) + ((old_y_int_0)*img->bufwidth)); + const unsigned c11_pos = 3*((old_x_int_1) + ((old_y_int_1)*img->bufwidth)); + + for (int i = 2; i >= 0 ; --i) { + const unsigned char c00 = img->buf[c00_pos + i]; + const unsigned char c01 = img->buf[c01_pos + i]; + const unsigned char c10 = img->buf[c10_pos + i]; + const unsigned char c11 = img->buf[c11_pos + i]; + + const double x_result_0 = (double)c00*x_factor + (double)c10*(1.0 - x_factor); + const double x_result_1 = (double)c01*x_factor + (double)c11*(1.0 - x_factor); + const double result = x_result_0*y_factor + x_result_1*(1.0 - y_factor); + + *newBuf++ = double_to_uchar_clamp255(result); + } newBuf++; - bufx += dx; } newBuf += jdy; } |