Description: So if I convert a file via Microsoft Office the pdf looks different from the one produced by Libreoffice Steps to Reproduce: 1.Open powerpoint File 2.Convert to PDF Actual Results: PDF should look the same as the one produced by microsoft office Expected Results: The PDF looks different than the one produced by MicroSoft Office Reproducible: Always User Profile Reset: No Additional Info: Version: 7.6.2.1 (X86_64) / LibreOffice Community Build ID: 56f7684011345957bbf33a7ee678afaf4d2ba333 CPU threads: 16; OS: Windows 10.0 Build 22621; UI render: Skia/Vulkan; VCL: win Locale: en-US (en_US); UI: en-US Calc: CL threaded
Created attachment 190184 [details] The pdf file produced by LibreOffice
Created attachment 190185 [details] The pdf file produced by Microsoft Office
Created attachment 190186 [details] Original File
The issue is with Impress opening that file, those images renders bad. Not exporting to PDF. But opening with PowerPoint, seems something is wrong with the contrast of those images, they render more light, but they have a negative contrast. Changing the contrast to 0, looks like in Impress. Seems Impress import it like 0 contrast. And there are a lot of objects of the same type with the same name. Please, @Regina could you take a look.
The objects, which render wrong, are rectangles with bitmap fill. The values for contrast and brightness belong to the "a:lum" attribute in ooxml. They are correctly read to maBlipProps in FillProperties. But they are not evaluated in FillProperties::pushToPropMap() in https://opengrok.libreoffice.org/xref/core/oox/source/drawingml/fillproperties.cxx?r=5fd0d769#409 These values should be applied to the graphic in case XML_blipFill, but they are not. There exist no attributes for these values for the rectangle, so they have to be applied to the graphic directly. It is likely, that something similar to lclGreysScaleGraphic in line 579-580 has to be done for contrast and brightness too.