Hi, I want to make a 1280x720 presentation. When I go to the properties window, it will only allow me to set the page size in cm.
How do I make my presentation 1280x720?
I don’t believe setting presentation slide size in pixels is possible (though it is I think on the wish list). AIUI Impress (and Powerpoint) were written to create printed acetate slides for Overhead Projectors, sized in cm or inches, and the file format and program specification are written round this - the concept of showing presentations on computer screens/digital projector came much later.
Set slide ‘paper size’ to Screen 16:9 (required format), and go with the flow.
If accurate sizes in pixels are required, there is an ‘Export as Images’ extension, which can create image files, for resizing as required
This is possible without extensions, via a workaround.
The size can be set from Slide -> Properties -> Page (tab)
Begin by setting the presentation size to “Screen 16:9” and view the page size in inches. For me this shows 11.02 (width) by 6.20 (height).
Next, click OK and pretend to export the page to a PNG from File -> Export... and saving the file as a temporary PNG file, entering the name as (for instance) temp.png. The next dialog produces the export size in pixels; for this example, I see 1058 (width) by 595 (height).
These, together, produce a pixels/inch ratio: 1058/11.02 = 96.01 and 595/6.20 = 95.97, both of which agree with the stated resolution below these: 96 pixels/inch. You can now cancel the export.
I demonstrated the process of acquiring the resolution in case the defaults change in the future.
Once you know the resolution, you can return to Slide -> Properties -> Page (tab) to set a User-specified size in inches. Just divide the desired size by the resolution and enter the value in inches.
For instance, if I want a slide of size 1280 (width) by 720 (height), this becomes 1280/96 = 13.3333 inches by 720/96 = 7.5 inches. Setting the Format to User, Width to 13.3333" and Height to 7.5" achieves this.
I would then confirm that the resolution is correct by again attempting a dummy Export to PNG and checking the output resolution. Due to rounding, I may need to adjust the output resolution on the export for the longer dimension.
My experience so far has been that the longer dimension has always remained within sufficient tolerance necessary to export exactly the desired resolution, even after the shorter dimension has been proportionately scaled as a result of that change. However, I think this fact is not strictly guaranteed, depending on internal precision and rounding accuracy for the user-specified widths and heights in inches.
Note: I am using Version: 6.0.7.3 (included in Ubuntu 18.04).