[MagickCore] SetImageType not working

The MagickWand interface is a new high-level C API interface to ImageMagick core methods. We discourage the use of the core methods and encourage the use of this API instead. Post MagickWand questions, bug reports, and suggestions to this forum.
Post Reply
aliksend
Posts: 1
Joined: 2016-01-11T07:24:51-07:00
Authentication code: 1151

[MagickCore] SetImageType not working

Post by aliksend » 2016-01-11T07:59:54-07:00

Hello
I'm using golang and this (https://github.com/quirkey/magick) package to resizing images in my project. All images are in sRGB colorspace.
And all was great, until I needed to resize an image, that contains only black and white colors. After convertation, image became terrible. I thought that reason in colorspaces and playing with it, but it has not given a satisfactory result.
With

Code: Select all

identify converted.png
before I have seen changings in colorspaces. But no result...
After internet-digging I found this case:

Code: Select all

identify -format "%[colorspace]"
and I saw that all converted before images was Gray.
And I found type option! http://www.imagemagick.org/script/comma ... s.php#type This is exactly what I needed. I used it with TrueColorMatte and saw that image is resized, looking good and still in sRGB.
And question: How I can use this option in my go code? I founded this method in MagickCore API: http://www.imagemagick.org/api/attribut ... tImageType and it looks like what I need, but it has no effect, image still Gray.
I wrote this code to test it:

Code: Select all

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <magick/MagickCore.h>

MagickBooleanType CheckException(ExceptionInfo *exception)
{
        register const ExceptionInfo
        *p;
        int haserr = 0;

        assert(exception != (ExceptionInfo *) NULL);
        assert(exception->signature == MagickSignature);
        if (exception->exceptions  == (void *) NULL)
                return MagickFalse;

        LockSemaphoreInfo(exception->semaphore);
        ResetLinkedListIterator((LinkedListInfo *) exception->exceptions);
        p=(const ExceptionInfo *) GetNextValueInLinkedList((LinkedListInfo *)
                                                           exception->exceptions);
        while (p != (const ExceptionInfo *) NULL)
        {
                if ((p->severity >= WarningException) && (p->severity < ErrorException))
                        haserr = 1;
                if ((p->severity >= ErrorException) && (p->severity < FatalErrorException))
                        haserr = 1;
                if (p->severity >= FatalErrorException)
                        haserr = 1;
                p=(const ExceptionInfo *) GetNextValueInLinkedList((LinkedListInfo *)
                                                                   exception->exceptions);
        }
        UnlockSemaphoreInfo(exception->semaphore);
        return haserr == 0 ? MagickFalse : MagickTrue;
}

int main() {
        printf("Started\n");

        // --- open img
        ExceptionInfo *exception = AcquireExceptionInfo();
        ImageInfo *info = AcquireImageInfo();
        char* c_filename = "original.png";
        (void) CopyMagickString(info->filename,c_filename,MaxTextExtent);
        Image *image = ReadImage(info, exception);
        MagickBooleanType failed = CheckException(exception);
        if (failed == MagickTrue) {
                DestroyImageInfo(info);
                printf("All bad (open)\n");
                // return nil, ErrorFromExceptionInfo(exception)
                return 1;
        }
        DestroyExceptionInfo(exception);
        // ---

        // --- do resize
        exception = AcquireExceptionInfo();
        image = AdaptiveResizeImage(image, 100, 100, exception);
        DestroyExceptionInfo(exception);
        // ---

        // -- do type
        MagickBooleanType success = SetImageType(image, TrueColorMatteType);
        if (success != MagickTrue) {
                printf("All bad (set type)\n");
        }
        // ---

        // --- save img
        exception = AcquireExceptionInfo();
        char* c_outpath = "converted.png";
        CopyMagickString(info->filename,c_outpath,MaxTextExtent);
        success = WriteImages(info, image, c_outpath, exception);
        failed = CheckException(exception);
        if (failed == MagickTrue) {
                DestroyImageInfo(info);
                printf("All bad (close f)\n");
                // return nil, ErrorFromExceptionInfo(exception)
                return 1;
        }
        if (success != MagickTrue) {
                printf("All bad (close s)\n");
        }
        DestroyExceptionInfo(exception);
        // ---

        printf("All done!\n");
}
It doesn't matter when I call SetImageType (before of after resizing), image is still Gray.
Am I doing something wrong?

PS I can write go wrapper to this C-function, but I need a working solution on C at least

snibgo
Posts: 12152
Joined: 2010-01-23T23:01:33-07:00
Authentication code: 1151
Location: England, UK

Re: [MagickCore] SetImageType not working

Post by snibgo » 2016-01-11T09:59:21-07:00

Try it with:

Code: Select all

char* c_outpath = "PNG24:converted.png";
snibgo's IM pages: im.snibgo.com

Post Reply