I have a pdf with multiple pages (so doing the following manually is not an option).
Each page has text with a bright green strip bordering part of each page.
How can I replace it with a solid color (white preferred) so that it fits the rest of the page?
I tried searching
pdftk overlay white
but I'm still not sure how to create an alpha overlay (so that it will only cover the green part, but not the text).
Note: The green strip is at the same position for each page.
I also tried overlaying a white pdf page (created by exporting blank page as PDF from LibreOffice's menu) on top of the one with the strip, but the whole page turns white! (The original page is below the overlay)
How can I make the exported PDF completely transparent, except where I want it to be white?
Turns out we need to turn an image (with alpha channel) into a PDF first.
convert image.png image.pdf
Then stamp image.pdf onto the original pdf
pdftk original.pdf stamp image.pdf output output.pdf
Related
This question is related to What is the smallest possible valid PDF?, but goes one step further: I'd like a PDF file that is as small as possible, but also invisible.
That means:
it contains no text or other objects (or if that's not possible, only completely transparent ones), and
it has no background (or if that's not possible, a completely transparent background).
When I open this file in a compliant PDF viewer, the background color of the viewer panel should show through completely, and when I embed it in a document on top of other elements, only these other elements should show.
PDF pages have no background color by default (if you need an explicit background you have to draw a colored rectangle that covers the entire page).
PDF viewers will use a default white background to simulate a paper page, so the actual background depends on the PDF viewer.
When you place a PDF page on top of another one it will not block the underlying content if it does not have an explicit background.
I have a Illustrator CS5 AI file that has two shapes in it on a transparent background/artboard. However, when I save this file as a SVG file (1.1) using "Save as", the resulting SVG file has a white background.
How do I get rid of the white background in the SVG file?
The AI file can be found here:
http://hostsafe.com/temp/in.ai
The SVG file that I keep getting can be found here:
http://hostsafe.com/temp/in.svg
Exported svg does not contain white background, it is just another view mode (hidden transparency grid). To show the transparency grid again go to 'View->Show Transparency Grid' or press Shift+Ctrl+D.
My Professor uses a very hard to see white font colour for about half of his lecture notes.
it is very hard to see on the slides, even worse printed out.
Is there a dynamic way to convert all white text in the entire document to black? hopefully there is a solution with Adobe Acrobat Pro DC which is what i am using, but im open to other suggestions.
In the Accessibility preferences, you can change the way text and line art is displayed. This isn't a permanent change but just changes how the PDF is drawn to the screen.
I have to put an image (.png) into a pdf file using LibHaru. The image has a transparent background due to which it looks quite awkward (black background) into the pdf file.
How can I put this image (with transparent background) properly using C++ LibHaru?
You need to split your PNG file into two images: one for color pixels and another one for opacity values. Then you need to add the color image into PDF with specifying the second as SMASK property.
See 4.8.4 Image Dictionaries in PDF specification for more details.
You can use HPDF_Image_AddSMask method for this.
I am having some problems with the PDF files that I make using the PDFSharp library. The files are ok as long as I am viewing them normally.
However I need these files to be changed using the accessibility options (Edit -> Preferences -> Accessibility (in the left menu Categories) -> Report Document Colors -> Custom Color). Whenever there is image with transperancy and/or transparent masks and the Background color is set to black everything disappears.
I looked at the PDFSharp code and it seems that they are setting some transparent SMask, which I did not find to do anything noticeable (at least for me), but I am not sure if I disable it will it screw up something that I cannot think of.
Most probably I won't get help on this one, but I hope that someone knows something more about this problem with PDF Transparency and the Accessibility options.
The transparency mask is created for images with transparency only.
So if your images contain black lines and a transparent background and you change the color of PDF pages to black, you will see black lines on a black background - you will see nothing.
If your images contain black lines on a white background, you will see your image as you know it: black lines on a white background.
Transparency is a feature, it's optional.
Maybe there's a bug in PDFsharp. If I watch the output of the Graphics sample with black background color, pages 4 and 5 are completely black (looks wrong to me).
The output of the Hello MigraDoc sample looks correct to me. The image on page 1 does not use transparency and keeps it white background, the chart on page 6 is transparent (which leads to black lines on a black background).
But maybe that's a bug in Adobe Reader - everything looks fine if I do not set a background color, but activate the transparency grid instead.
If you think that your images do not contain transparency, then we'll need files (PDF and image) for further examination.
Edit: I just checked the output of the Graphics sample with Adobe Acrobat 5 - all pages display correctly even with black background color. With Adobe Acrobat 8 and Adobe Reader X pages 4 and 5 are black. Looks like a bug in Adobe Acrobat/Reader to me.