sent-bilinearscaling-1.0.diff (2979B)
1 diff --git a/sent.c b/sent.c 2 index 0da2bff..d92cf3b 100644 3 --- a/sent.c 4 +++ b/sent.c 5 @@ -282,27 +282,66 @@ ffprepare(Image *img) 6 img->state |= SCALED; 7 } 8 9 +static unsigned char double_to_uchar_clamp255(double dbl) 10 +{ 11 + dbl = round(dbl); 12 + 13 + return 14 + (dbl < 0.0) ? 0 : 15 + (dbl > 255.0) ? 255 : (unsigned char)dbl; 16 +} 17 + 18 +static int int_clamp(int integer, int lower, int upper) 19 +{ 20 + if (integer < lower) 21 + return lower; 22 + else if (integer >= upper) 23 + return upper - 1; 24 + else 25 + return integer; 26 +} 27 + 28 void 29 ffscale(Image *img) 30 { 31 - unsigned int x, y; 32 - unsigned int width = img->ximg->width; 33 - unsigned int height = img->ximg->height; 34 - char* newBuf = img->ximg->data; 35 - unsigned char* ibuf; 36 - unsigned int jdy = img->ximg->bytes_per_line / 4 - width; 37 - unsigned int dx = (img->bufwidth << 10) / width; 38 - 39 - for (y = 0; y < height; y++) { 40 - unsigned int bufx = img->bufwidth / width; 41 - ibuf = &img->buf[y * img->bufheight / height * img->bufwidth * 3]; 42 - 43 - for (x = 0; x < width; x++) { 44 - *newBuf++ = (ibuf[(bufx >> 10)*3+2]); 45 - *newBuf++ = (ibuf[(bufx >> 10)*3+1]); 46 - *newBuf++ = (ibuf[(bufx >> 10)*3+0]); 47 + const unsigned width = img->ximg->width; 48 + const unsigned height = img->ximg->height; 49 + unsigned char* newBuf = (unsigned char*)img->ximg->data; 50 + const unsigned jdy = img->ximg->bytes_per_line / 4 - width; 51 + 52 + const double x_scale = ((double)img->bufwidth/(double)width); 53 + const double y_scale = ((double)img->bufheight/(double)height); 54 + 55 + for (unsigned y = 0; y < height; ++y) { 56 + const double old_y = (double)y * y_scale; 57 + const double y_factor = ceil(old_y) - old_y; 58 + const int old_y_int_0 = int_clamp((int)floor(old_y), 0, img->bufheight); 59 + const int old_y_int_1 = int_clamp((int)ceil(old_y), 0, img->bufheight); 60 + 61 + for (unsigned x = 0; x < width; ++x) { 62 + const double old_x = (double)x * x_scale; 63 + const double x_factor = ceil(old_x) - old_x; 64 + const int old_x_int_0 = int_clamp((int)floor(old_x), 0, img->bufwidth); 65 + const int old_x_int_1 = int_clamp((int)ceil(old_x), 0, img->bufwidth); 66 + 67 + const unsigned c00_pos = 3*((old_x_int_0) + ((old_y_int_0)*img->bufwidth)); 68 + const unsigned c01_pos = 3*((old_x_int_0) + ((old_y_int_1)*img->bufwidth)); 69 + const unsigned c10_pos = 3*((old_x_int_1) + ((old_y_int_0)*img->bufwidth)); 70 + const unsigned c11_pos = 3*((old_x_int_1) + ((old_y_int_1)*img->bufwidth)); 71 + 72 + for (int i = 2; i >= 0 ; --i) { 73 + const unsigned char c00 = img->buf[c00_pos + i]; 74 + const unsigned char c01 = img->buf[c01_pos + i]; 75 + const unsigned char c10 = img->buf[c10_pos + i]; 76 + const unsigned char c11 = img->buf[c11_pos + i]; 77 + 78 + const double x_result_0 = (double)c00*x_factor + (double)c10*(1.0 - x_factor); 79 + const double x_result_1 = (double)c01*x_factor + (double)c11*(1.0 - x_factor); 80 + const double result = x_result_0*y_factor + x_result_1*(1.0 - y_factor); 81 + 82 + *newBuf++ = double_to_uchar_clamp255(result); 83 + } 84 newBuf++; 85 - bufx += dx; 86 } 87 newBuf += jdy; 88 }