REG:

[Mohan Selvaraj]

Hi,

Is there any API to find the rotation of the individual characters in a PDF page? How to find the angle of the  individual characters in the document using PDFium?

            IntPtr textPage = PdfiumViewer.FPDFText_LoadPage(pages); // retrieved the texpage

int charCount = PdfiumViewer.FPDFText_CountChars(textPage);

            byte[] characters = new byte[(charCount + 1) * 2];

            PdfiumViewer.FPDFText_GetText(textPage, 0, charCount + 1, characters);

            string extractedText = string.Empty;

            for (int j = 0; j < charCount; j++)

            {

                uint unicodeCharacter = PdfiumViewer.FPDFText_GetUnicode(textPage, j);

                extractedText += ((char)unicodeCharacter).ToString(); // Need to get the rotation angle for the individual text

            }

Regards,

Mohan S 

[Olivia Yingst]

Hi Mohan, 

Maybe you can try to use the API FPDFText_GetMatrix(). This should return the transformation matrix for a particular character. Then you can calculate the rotation angle from the matrix.

Regards,

Olivia

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Olivia(Hui) Yingst |

Software Engineer |

huiy...@google.com |

213-399-8487

[Desika R]

Hi Team,

Thanks for your update,

We have tried this below code to get the rotation angle for the individual text. But it returns Zero for the rotated text. Kindly suggest us to retrieve the rotation of the character.

            double m1, m2, m3, m4, m5, m6;

            PdfiumViewer.FPDFText_GetMatrix(textObjects[index], out m1, out m2, out m3, out m4, out m5, out m6);

            double radians = Math.Atan2(m3, m1);

            int textRotation = (int)(radians * 180 / Math.PI);

            return textRotation;

Regards,

Desika

 

[Lei Zhang]

Please provide a sample PDF that demonstrates the issue. The code
looks ok for calculating the rotation of the text only, but there may
be other transformation matrices in effect. A sample PDF will help
determine why your code returns 0.

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[Desika R]

Hi Team,

Please find the sample PDF to replicate the issue.

Regards,

Desika

[Lei Zhang]

In this sample PDF, the rotation comes from page rotation, not
character rotation. Looking at object 1 0, the page object for the 1st
page, The /CropBox and /MediaBox are both [0 0 595 842]. This looks
like a portrait page, except the page object also has /Rotation 270.
Thus PDF Viewers display the page in landscape mode. Use
FPDFPage_GetRotation() to get the page rotation.

> To view this discussion on the web visit https://groups.google.com/d/msgid/pdfium/9710a659-8d8c-4d64-8405-564e36a827c1n%40googlegroups.com.