Best way to process images on PDF files

Example requests & Code samples for GdPicture Toolkits.
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fervelas
Posts: 6
Joined: Tue Aug 08, 2017 5:09 am

Best way to process images on PDF files

Post by fervelas » Tue Sep 26, 2017 8:52 am

Hey guys,

I'm currently using the latest release of GdPicture v14. The system we're building will mostly handle image-only PDF files and a few TIFF files. Most cleanup and manipulation operations with TIFF files are trivial to implement by using a GdPictureImaging object, but I don't know if there is an easier way to do it when handling PDF files. This is an extract of a cropping operation on a PDF file composed of all images:

Code: Select all

            //This assumes that the first page is selected and shown on a GdViewer and that the user has previously selected an area on the viewer
            float top = 0, left = 0, width = 0, height = 0;
            //extract the pdf page as an image
            int tempImage = gdPdf.RenderPageToGdPictureImage(200, false);
            //get the dimensions and position of the selected area
            imageViewer.GetRectCoordinatesOnDocumentInches(ref left, ref top, ref width, ref height);
            left *= 200;
            top *= 200;
            width *= 200;
            height *= 200;
            //crop the image to the dimensions of the selected area
            gdPicture.Crop(tempImage, (int)left, (int)top, (int)width, (int)height);
            //remove the original page from the pdf file
            gdPdf.DeletePage(1);
            //insert a new, blank page
            gdPdf.InsertPage(width, height, 1);
            //add the cropped image as a resource to the pdf
            string imageResx = gdPdf.AddImageFromGdPictureImage(tempImage, false, false);
            //draw it on the first page
            gdPdf.DrawImage(imageResx, 0, 0, width, height);
            //refresh viewer and thumbnails
            imageViewer.Redraw();
            thumbnailViewer.RedrawItem(0);
This proof of concept snippet works for me, but I feel it's a bit overkill compared to the simplicity involved in doing the same thing with a TIFF file, which only takes 3 lines of code to accomplish the same crop operation. There are other cleanup operations that I'll be performing in the system so I would appreciate it if you guys can shed some light as to better practices while working with image-only PDFs to avoid too much code complexity and to provide fast image manipulation in these cases.

Many thanks in advance for any advice I can get!

Gabriela
Posts: 378
Joined: Wed Nov 22, 2017 9:52 am

Re: Best way to process images on PDF files

Post by Gabriela » Mon Jan 21, 2019 2:45 pm

Hi,

The PDF format is not primarily intended for use with images only. Because of this, although your code snippet may contain more lines of code, it looks good and it is working well. Anyway, we can offer a couple of new methods you might find useful when working with image-based PDFs only:
http://guides.gdpicture.com/content/web ... eskew.html
http://guides.gdpicture.com/content/web ... geMRC.html
In most cases, it depends on the workflow and on your requirements, what are you trying to achieve.
Kind regards,

Gabriela
GdPicture Team

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