Inserted images are too big

[SarrasiM]

Good morning,

I've been experimenting with the page insertion in PDF lately and I can't figure out why the pages that are added to an existing PDF are oversized. It does not happen when I append image. You can see the the actual view after insertion (text have been redacted) in the os.png attachment.

Following is the code snippet used:

Code: Select all

        private static void Insert(GdPictureImaging gdp)
        {
            var position = 3;
            var searchable = true;
            var idx = 1;
            var inserts = Directory.GetFiles(@".\add");

            var pdf = new GdPicturePDF();

            pdf.LoadFromFile(@".\base.pdf", true);
           
            if (position > 0) { 
                idx = position;
            }
            else
                idx = pdf.GetPageCount();

            foreach (var insert in inserts)
            {
                var id = gdp.CreateGdPictureImageFromFile(insert);

                if (position == -1) { 
                    pdf.AddImageFromGdPictureImage(id, PdfAdvancedImageCompression.PdfAdvancedImageCompressionColorDetection);

                    pdf.SelectPage(++idx);                    
                }
                else
                {
                    var res = pdf.AddImageFromGdPictureImage(id, false, false);
                    var width = (float)gdp.GetWidth(id);
                    var height = (float)gdp.GetHeight(id);
                                                            
                    pdf.InsertPage(width, height, idx);
                    pdf.SelectPage(idx++);
                    pdf.DrawImage(res, 0, 0, width, height);
                }

                if (searchable)
                    pdf.OcrPage("eng+fra", @".\data", string.Empty, 200f);
            }

            pdf.SaveToFile(@".\base.pdf");
            pdf.Dispose();
        }

I suspect this might be a measurement unit problem. The 'base.pdf' file is generated with Adobe Acrobat Pro from multiple combined images.

Thanks for your help!

[Cedric]

First thing is that you cannot use pixel because the resolution concept does not exist in PDF, therefore you have to convert your image height and width to inches.
This is definitely a measurement unit problem, you do not define the unit to use which you should by calling this method : https://www.gdpicture.com/guides/gdpicture/we ... tUnit.html

[SarrasiM]

Hello Cedric,

I've changed the code so that the 'width' and 'height' variables are respectively set to '8.5' and '11' with tis code:
var width = (float)gdp.GetWidth(id) / (float)gdp.GetHorizontalResolution(id); // 8.5
var height = (float)gdp.GetHeight(id) / (float)gdp.GetVerticalResolution(id); // 11

Those are then passed to InsertPage() and DrawImage(). The result is now the total opposite, the images are undersized as shown in the attached file. Could you elaborate a little more on how that convertion is done, if it's not the actual inches size?

Thanks,

[Cedric]

Please read my previous answer. Setting a size without first setting the measurement unit to use makes sense.
The default is most probably point (which is 1/72 inch) so it would explain why it is now undersized.

[SarrasiM]

Cedric, the measurement unit is set to this pdf.SetMeasurementUnit(PdfMeasurementUnit.PdfMeasurementUnitInch).

[SarrasiM]

Got it! I was setting the PDF measurement before reloading a PDF. Thanks Cedric