Re: getting a page from a PDF with core

Hi Bob, thank you very much for the help, it's working well.

On 17 April 2016 at 17:37, Bob Friesenhahn <[email protected]> wrote:
>> I found the ->scene member, which seems to be what Wand uses, but I
>> can't get it to work. This test program seems to always render the
>> whole PDF and then pick out page zero:
>
> What you are wanting is 'subimage' and 'subrange' in ImageInfo.
> These need to be specified in the image_info struct which is passed to
> ReadImage.
>
> subimage - Starting image scene ID to select
> subrange - Span of image scene IDs (from starting scene) to select

You'll be astonished to hear that IM has deprecated these fields in
favour of "scene" and "number_scenes". You need to set the string
version of "scene" as well, I'm not sure why.

Summary in case anyone else ever asks:

GM needs

        image_info->subimage = page number, as an unsigned long;
        image_info->subrange = number of ranges, as an unsigned long;

IM needs

        read->image_info->scene = page number, as a size_t;
        read->image_info->number_scenes = number of pages, as a size_t;
        char page[256];
        snprintf( page, 256, "%zd", read->image_info->scene );
        read->image_info->scenes = strdup( page );

John

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