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Add a test suite to do a bunch of different resizes to find problems. One problem found was an incorrect calculation of texel support how many margin texels needed when downsampling. When downsampling we need to spread out the support of each contributing texel, so to compensate you need more margin texels.

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This commit is contained in:
Jorge Rodriguez
2014-07-29 22:50:06 -07:00
parent 68f93b72d5
commit ebe0473d8b
2 changed files with 120 additions and 48 deletions
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59
tests/resample_test.cpp
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@ -18,6 +18,8 @@
#include <sys/timeb.h>
#endif
void test_suite();
int main(int argc, char** argv)
{
unsigned char* input_data;
@ -26,6 +28,11 @@ int main(int argc, char** argv)
int n;
int out_w, out_h, out_stride;
#if 1
test_suite();
return 0;
#endif
if (argc <= 1)
{
printf("No input image\n");
@ -87,3 +94,55 @@ int main(int argc, char** argv)
return 0;
}
void resize_image(const char* filename, float width_percent, float height_percent, stbr_filter filter, stbr_edge edge, const char* output_filename)
{
int w, h, n;
unsigned char* input_data = stbi_load(filename, &w, &h, &n, 0);
if (!input_data)
{
printf("Input image could not be loaded");
return;
}
int out_w = (int)(w * width_percent);
int out_h = (int)(h * height_percent);
unsigned char* output_data = (unsigned char*)malloc(out_w * out_h * n);
size_t memory_required = stbr_calculate_memory(w, h, out_w, out_h, n, filter);
void* extra_memory = malloc(memory_required);
stbr_resize_arbitrary(input_data, w, h, 0, output_data, out_w, out_h, 0, n, STBR_TYPE_UINT8, filter, edge, STBR_COLORSPACE_SRGB, extra_memory, memory_required);
free(extra_memory);
stbi_write_png(output_filename, out_w, out_h, n, output_data, 0);
free(output_data);
}
void test_suite()
{
// sRGB tests
resize_image("gamma_colors.jpg", .5f, .5f, STBR_FILTER_CATMULLROM, STBR_EDGE_REFLECT, "test-output/gamma_colors.jpg");
resize_image("gamma_2.2.jpg", .5f, .5f, STBR_FILTER_CATMULLROM, STBR_EDGE_REFLECT, "test-output/gamma_2.2.jpg");
resize_image("gamma_dalai_lama_gray.jpg", .5f, .5f, STBR_FILTER_CATMULLROM, STBR_EDGE_REFLECT, "test-output/gamma_dalai_lama_gray.jpg");
for (int i = 10; i < 100; i++)
{
char outname[200];
sprintf(outname, "test-output/barbara-width-%d.jpg", i);
resize_image("barbara.png", (float)i / 100, 1, STBR_FILTER_CATMULLROM, STBR_EDGE_CLAMP, outname);
}
for (int i = 110; i < 1000; i += 10)
{
char outname[200];
sprintf(outname, "test-output/barbara-width-%d.jpg", i);
resize_image("barbara.png", (float)i / 100, 1, STBR_FILTER_CATMULLROM, STBR_EDGE_CLAMP, outname);
}
}