diff --git a/stb_image_resize.h b/stb_image_resize.h index b0699ba..9177d14 100644 --- a/stb_image_resize.h +++ b/stb_image_resize.h @@ -2229,8 +2229,8 @@ static void stbir__calculate_transform(stbir__info *info, float s0, float t0, fl info->horizontal_scale = ((float)info->output_w / info->input_w) / (s1 - s0); info->vertical_scale = ((float)info->output_h / info->input_h) / (t1 - t0); - info->horizontal_shift = s0 * info->input_w / (s1 - s0); - info->vertical_shift = t0 * info->input_h / (t1 - t0); + info->horizontal_shift = s0 * info->output_w / (s1 - s0); + info->vertical_shift = t0 * info->output_h / (t1 - t0); } } diff --git a/tests/resample_test.cpp b/tests/resample_test.cpp index c42df7b..2c4a56a 100644 --- a/tests/resample_test.cpp +++ b/tests/resample_test.cpp @@ -1,4 +1,5 @@ -#include +#include +#include #if defined(_WIN32) && _MSC_VER > 1200 #define STBIR_ASSERT(x) \ @@ -356,6 +357,54 @@ void test_subpixel(const char* file, float width_percent, float height_percent, free(output_data); } +void test_subpixel_region(const char* file, float width_percent, float height_percent, float s0, float t0, float s1, float t1) +{ + int w, h, n; + unsigned char* input_data = stbi_load(file, &w, &h, &n, 0); + + if (input_data == NULL) + return; + + int new_w = (int)(w * width_percent); + int new_h = (int)(h * height_percent); + + unsigned char* output_data = (unsigned char*)malloc(new_w * new_h * n * sizeof(unsigned char)); + + stbir_resize_region(input_data, w, h, 0, output_data, new_w, new_h, 0, STBIR_TYPE_UINT8, n, STBIR_ALPHA_CHANNEL_NONE, 0, STBIR_EDGE_CLAMP, STBIR_EDGE_CLAMP, STBIR_FILTER_BOX, STBIR_FILTER_CATMULLROM, STBIR_COLORSPACE_SRGB, &g_context, s0, t0, s1, t1); + + stbi_image_free(input_data); + + char output[200]; + sprintf(output, "test-output/subpixel-region-%d-%d-%f-%f-%f-%f-%s", new_w, new_h, s0, t0, s1, t1, file); + stbi_write_png(output, new_w, new_h, n, output_data, 0); + + free(output_data); +} + +void test_subpixel_command(const char* file, float width_percent, float height_percent, float x_scale, float y_scale, float x_offset, float y_offset) +{ + int w, h, n; + unsigned char* input_data = stbi_load(file, &w, &h, &n, 0); + + if (input_data == NULL) + return; + + int new_w = (int)(w * width_percent); + int new_h = (int)(h * height_percent); + + unsigned char* output_data = (unsigned char*)malloc(new_w * new_h * n * sizeof(unsigned char)); + + stbir_resize_subpixel(input_data, w, h, 0, output_data, new_w, new_h, 0, STBIR_TYPE_UINT8, n, STBIR_ALPHA_CHANNEL_NONE, 0, STBIR_EDGE_CLAMP, STBIR_EDGE_CLAMP, STBIR_FILTER_BOX, STBIR_FILTER_CATMULLROM, STBIR_COLORSPACE_SRGB, &g_context, x_scale, y_scale, x_offset, y_offset); + + stbi_image_free(input_data); + + char output[200]; + sprintf(output, "test-output/subpixel-command-%d-%d-%f-%f-%f-%f-%s", new_w, new_h, x_scale, y_scale, x_offset, y_offset, file); + stbi_write_png(output, new_w, new_h, n, output_data, 0); + + free(output_data); +} + unsigned int* pixel(unsigned int* buffer, int x, int y, int c, int w, int n) { return &buffer[y*w*n + x*n + c]; @@ -461,6 +510,18 @@ void test_subpixel_1() STBIR_ASSERT(output_data[y * 16 + x + 8] == output_right[y * 8 + x]); } } + + stbir_resize_subpixel(image, 8, 8, 0, output_left, 8, 16, 0, STBIR_TYPE_UINT8, 1, STBIR_ALPHA_CHANNEL_NONE, 0, STBIR_EDGE_CLAMP, STBIR_EDGE_CLAMP, STBIR_FILTER_CATMULLROM, STBIR_FILTER_CATMULLROM, STBIR_COLORSPACE_SRGB, &g_context, 2, 2, 0, 0); + stbir_resize_subpixel(image, 8, 8, 0, output_right, 8, 16, 0, STBIR_TYPE_UINT8, 1, STBIR_ALPHA_CHANNEL_NONE, 0, STBIR_EDGE_CLAMP, STBIR_EDGE_CLAMP, STBIR_FILTER_CATMULLROM, STBIR_FILTER_CATMULLROM, STBIR_COLORSPACE_SRGB, &g_context, 2, 2, 8, 0); + + {for (int x = 0; x < 8; x++) + { + for (int y = 0; y < 16; y++) + { + STBIR_ASSERT(output_data[y * 16 + x] == output_left[y * 8 + x]); + STBIR_ASSERT(output_data[y * 16 + x + 8] == output_right[y * 8 + x]); + } + }} } // test that replicating an image and using a subtile of it produces same results as wraparound @@ -498,6 +559,14 @@ void test_subpixel_2() for (int y = 0; y < 16; y++) STBIR_ASSERT(output_data_1[y * 16 + x] == output_data_2[y * 16 + x]); }} + + stbir_resize_subpixel(large_image, 32, 32, 0, output_data_2, 16, 16, 0, STBIR_TYPE_UINT8, 1, STBIR_ALPHA_CHANNEL_NONE, 0, STBIR_EDGE_WRAP, STBIR_EDGE_WRAP, STBIR_FILTER_CATMULLROM, STBIR_FILTER_CATMULLROM, STBIR_COLORSPACE_SRGB, &g_context, 2, 2, 16, 16); + + {for (int x = 0; x < 16; x++) + { + for (int y = 0; y < 16; y++) + STBIR_ASSERT(output_data_1[y * 16 + x] == output_data_2[y * 16 + x]); + }} } // test that 0,0,1,1 subpixel produces same result as no-rect @@ -521,6 +590,14 @@ void test_subpixel_3() for (int y = 0; y < 32; y++) STBIR_ASSERT(output_data_1[y * 32 + x] == output_data_2[y * 32 + x]); } + + stbir_resize_subpixel(image, 8, 8, 0, output_data_1, 32, 32, 0, STBIR_TYPE_UINT8, 1, 0, STBIR_ALPHA_CHANNEL_NONE, STBIR_EDGE_CLAMP, STBIR_EDGE_CLAMP, STBIR_FILTER_CATMULLROM, STBIR_FILTER_CATMULLROM, STBIR_COLORSPACE_LINEAR, NULL, 4, 4, 0, 0); + + {for (int x = 0; x < 32; x++) + { + for (int y = 0; y < 32; y++) + STBIR_ASSERT(output_data_1[y * 32 + x] == output_data_2[y * 32 + x]); + }} } // test that 1:1 resample using s,t=0,0,1,1 with bilinear produces original image @@ -537,6 +614,9 @@ void test_subpixel_4() stbir_resize_region(image, 8, 8, 0, output, 8, 8, 0, STBIR_TYPE_UINT8, 1, STBIR_ALPHA_CHANNEL_NONE, 0, STBIR_EDGE_CLAMP, STBIR_EDGE_CLAMP, STBIR_FILTER_TRIANGLE, STBIR_FILTER_TRIANGLE, STBIR_COLORSPACE_LINEAR, &g_context, 0, 0, 1, 1); STBIR_ASSERT(memcmp(image, output, 8 * 8) == 0); + + stbir_resize_subpixel(image, 8, 8, 0, output, 8, 8, 0, STBIR_TYPE_UINT8, 1, STBIR_ALPHA_CHANNEL_NONE, 0, STBIR_EDGE_CLAMP, STBIR_EDGE_CLAMP, STBIR_FILTER_TRIANGLE, STBIR_FILTER_TRIANGLE, STBIR_COLORSPACE_LINEAR, &g_context, 1, 1, 0, 0); + STBIR_ASSERT(memcmp(image, output, 8 * 8) == 0); } static unsigned int image88_int[8][8]; @@ -880,17 +960,70 @@ void test_suite(int argc, char **argv) stbir_resize(image88, 8, 8, 0, output88, 16, 4, 0, STBIR_TYPE_UINT8, 1, STBIR_ALPHA_CHANNEL_NONE, 0, STBIR_EDGE_CLAMP, STBIR_EDGE_CLAMP, STBIR_FILTER_BOX, STBIR_FILTER_CATMULLROM, STBIR_COLORSPACE_SRGB, &g_context); stbir_resize(image88, 8, 8, 0, output88, 16, 4, 0, STBIR_TYPE_UINT8, 1, STBIR_ALPHA_CHANNEL_NONE, 0, STBIR_EDGE_CLAMP, STBIR_EDGE_CLAMP, STBIR_FILTER_CATMULLROM, STBIR_FILTER_BOX, STBIR_COLORSPACE_SRGB, &g_context); - for (i = 0; i < 10; i++) + int barbara_width, barbara_height, barbara_channels; + stbi_image_free(stbi_load(barbara, &barbara_width, &barbara_height, &barbara_channels, 0)); + + int res = 10; + // Downscaling + {for (int i = 0; i <= res; i++) + { + float t = (float)i/res; + float scale = 0.5; + float out_scale = 2.0f/3; + float x_shift = (barbara_width*out_scale - barbara_width*scale) * t; + float y_shift = (barbara_height*out_scale - barbara_height*scale) * t; + + test_subpixel_command(barbara, scale, scale, out_scale, out_scale, x_shift, y_shift); + }} + + // Upscaling + {for (int i = 0; i <= res; i++) + { + float t = (float)i/res; + float scale = 2; + float out_scale = 3; + float x_shift = (barbara_width*out_scale - barbara_width*scale) * t; + float y_shift = (barbara_height*out_scale - barbara_height*scale) * t; + + test_subpixel_command(barbara, scale, scale, out_scale, out_scale, x_shift, y_shift); + }} + + // Downscaling + {for (int i = 0; i <= res; i++) + { + float t = (float)i/res / 2; + test_subpixel_region(barbara, 0.25f, 0.25f, t, t, t+0.5f, t+0.5f); + }} + + // No scaling + {for (int i = 0; i <= res; i++) + { + float t = (float)i/res / 2; + test_subpixel_region(barbara, 0.5f, 0.5f, t, t, t+0.5f, t+0.5f); + }} + + // Upscaling + {for (int i = 0; i <= res; i++) + { + float t = (float)i/res / 2; + test_subpixel_region(barbara, 1, 1, t, t, t+0.5f, t+0.5f); + }} + + {for (i = 0; i < 10; i++) test_subpixel(barbara, 0.5f, 0.5f, (float)i / 10, 1); + } - for (i = 0; i < 10; i++) + {for (i = 0; i < 10; i++) test_subpixel(barbara, 0.5f, 0.5f, 1, (float)i / 10); + } - for (i = 0; i < 10; i++) + {for (i = 0; i < 10; i++) test_subpixel(barbara, 2, 2, (float)i / 10, 1); + } - for (i = 0; i < 10; i++) + {for (i = 0; i < 10; i++) test_subpixel(barbara, 2, 2, 1, (float)i / 10); + } // Channels test test_channels(barbara, 0.5f, 0.5f, 1); @@ -916,40 +1049,40 @@ void test_suite(int argc, char **argv) resize_image(barbara, 0.5f, 0.5f, STBIR_FILTER_CATMULLROM , STBIR_EDGE_CLAMP, STBIR_COLORSPACE_SRGB, "test-output/barbara-downsample-catmullrom.png"); resize_image(barbara, 0.5f, 0.5f, STBIR_FILTER_MITCHELL , STBIR_EDGE_CLAMP, STBIR_COLORSPACE_SRGB, "test-output/barbara-downsample-mitchell.png"); - for (i = 10; i < 100; i++) + {for (i = 10; i < 100; i++) { char outname[200]; sprintf(outname, "test-output/barbara-width-%d.jpg", i); resize_image(barbara, (float)i / 100, 1, STBIR_FILTER_CATMULLROM, STBIR_EDGE_CLAMP, STBIR_COLORSPACE_SRGB, outname); - } + }} - for (i = 110; i < 500; i += 10) + {for (i = 110; i < 500; i += 10) { char outname[200]; sprintf(outname, "test-output/barbara-width-%d.jpg", i); resize_image(barbara, (float)i / 100, 1, STBIR_FILTER_CATMULLROM, STBIR_EDGE_CLAMP, STBIR_COLORSPACE_SRGB, outname); - } + }} - for (i = 10; i < 100; i++) + {for (i = 10; i < 100; i++) { char outname[200]; sprintf(outname, "test-output/barbara-height-%d.jpg", i); resize_image(barbara, 1, (float)i / 100, STBIR_FILTER_CATMULLROM, STBIR_EDGE_CLAMP, STBIR_COLORSPACE_SRGB, outname); - } + }} - for (i = 110; i < 500; i += 10) + {for (i = 110; i < 500; i += 10) { char outname[200]; sprintf(outname, "test-output/barbara-height-%d.jpg", i); resize_image(barbara, 1, (float)i / 100, STBIR_FILTER_CATMULLROM, STBIR_EDGE_CLAMP, STBIR_COLORSPACE_SRGB, outname); - } + }} - for (i = 50; i < 200; i += 10) + {for (i = 50; i < 200; i += 10) { char outname[200]; sprintf(outname, "test-output/barbara-width-height-%d.jpg", i); resize_image(barbara, 100 / (float)i, (float)i / 100, STBIR_FILTER_CATMULLROM, STBIR_EDGE_CLAMP, STBIR_COLORSPACE_SRGB, outname); - } + }} test_format(barbara, 0.5, 2.0, STBIR_TYPE_UINT16, STBIR_COLORSPACE_SRGB); test_format(barbara, 0.5, 2.0, STBIR_TYPE_UINT16, STBIR_COLORSPACE_LINEAR);