PixelGetBlueQuantum doesn't work in HDRI

[Danack]

The ImageMagick wand functions for getting colors as quantum values seem to not work. Code below gives the output:

Color pink Blue value is 0.796078, quantum adab
Color purple Blue value is 0.501961, quantum adab
Color red Blue value is 0.000000, quantum adab
Color blue Blue value is 1.000000, quantum adab

Coincidentally, 'adab' appears to be part of the MagickSignature:

"#define MagickSignature 0xabacadabUL"

Code: Select all

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <malloc.h>
#include <wand/MagickWand.h>

int main(int argc,char **argv) {
    int i;
    double blueValue;
    Quantum blueQuantum;
    
    MagickWandGenesis();
    char * color;
    
    PixelWand *pixel_wand = NULL;
    
    char *colors[] = {"pink", "purple", "red", "blue", "rgb(13, 13, 13)"};
    
    for (i=0; i<4 ; i++) {
    
        color = colors[i];
        
        pixel_wand = NewPixelWand();    
        PixelSetColor(pixel_wand, color);
    
        blueValue = PixelGetBlue(pixel_wand);
        blueQuantum = PixelGetBlueQuantum(pixel_wand);

        printf("Color %s \t Blue value is %f, quantum %x\n", color, blueValue, blueQuantum);

    }
    
    MagickWandTerminus();
    
    return(0);
}

[magick]

We changed %x to %d in your print statement and it returns expected results:

• Color pink Blue value is 0.796078, quantum 52171
  Color purple Blue value is 0.501961, quantum 32896
  Color red Blue value is 0.000000, quantum 0
  Color blue Blue value is 1.000000, quantum 65535

[Danack]

Hi,

It looks like the issue only occurs when ImageMagick is compiled with --enable-hdri for both Q16 and Q32.

Is calling PixelGetBlueQuantum a valid thing to do when ImageMagick has been compiled as the HDRI version?

cheers
Dan

[magick]

For HDRI, you need %g as the Quantum format specifier. We get:

• -> ./wand
  Color pink Blue value is 0.796078, quantum 52171.000000
  Color purple Blue value is 0.501961, quantum 32896.000000
  Color red Blue value is 0.000000, quantum 0.000000
  Color blue Blue value is 1.000000, quantum 65535.000000