I'm seeing a change in behaviour for IsPixelWandSimilar. In ImageMagick-6.9.0-6 and other later versions as well the behaviour of the function for a set of tests ( https://github.com/mkoppanen/imagick/bl ... milar.phpt ) works as expected.
For version ImageMagick-6.9.1-4 the behaviour is both different and appears to be wrong. I was going to say that the fuzz factor no longer needs to be scaled by the Quantum value. However the behaviour is more confusing than that, and I am not able to say exactly what is happening.
The code below is an extract from those tests - I can't figure out what the pattern is for the behaviour, but it seems that the behaviour of the function is now incorrect, no matter whether I scale the fuzz by QuantumRange or not.
cheers
Dan
Code: Select all
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <malloc.h>
#include <wand/MagickWand.h>
void testSimilar(char *color1, char *color2, float distance, int expectedResult) {
float fuzz ;
int status;
PixelWand *pixel_wand_1 = NULL;
PixelWand *pixel_wand_2 = NULL;
pixel_wand_1 = NewPixelWand();
PixelSetColor(pixel_wand_1, color1);
pixel_wand_2 = NewPixelWand();
PixelSetColor(pixel_wand_2, color2);
fuzz = distance / sqrt(3);
status = IsPixelWandSimilar(pixel_wand_1, pixel_wand_2, fuzz * QuantumRange);
//Removing the quantum range makes the first test work, and the others fail...
//status = IsPixelWandSimilar(pixel_wand_1, pixel_wand_2, fuzz );
printf("Expected %d actual %d for colors %s %s distance %f \n", expectedResult, status, color1, color2, distance);
}
int main(int argc,char **argv) {
MagickWandGenesis();
//Distance between points is 9.899494936611665
testSimilar("rgba(0, 0, 0, 1)", "rgba(7, 7, 0, 1)", 9, 0);
testSimilar("rgba(0, 0, 0, 1)", "rgba(7, 7, 0, 1)", 10, 1);
//Distance between points is 10
testSimilar("black", "rgba(10, 0, 0, 1.0)", 11, 1);
//Distance between points is 10
testSimilar("rgb(245, 0, 0)", "rgb(255, 0, 0)", 10, 1);
MagickWandTerminus();
return(0);
}
