pictview: PNG not displayed correctly

Discussion of bugs and problems found in Altap Salamander. In your reports, please be as descriptive as possible, and report one incident per report. Do not post crash reports here, send us the generated bug report by email instead, please.

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Joined: 09 Dec 2005, 15:13

Re: pictview: PNG not displayed correctly

Post by crystalidea » 21 Jan 2017, 15:43

Not fixed in 3.0.8

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Joined: 19 Dec 2017, 21:58

Re: pictview: PNG not displayed correctly

Post by maroon » 19 Dec 2017, 22:55

Unsure if the above Picview problem is related to mine. Seeing this in 32/64bit versions on Win7.

https://www.dropbox.com/sh/zw1hdr3shfvh ... _xuva?dl=0

F3 Pictview viewer for at least several Salamander versions has error "Unknown type of compression" unless there's an extra amount of image data beyond what's needed. And the required amount of extra data increases as width x height increases.

For an 800x600 image, PNG should only need 800 x 600 / 8 = 60000 bytes, but F3 won't view unless memory image has at least 500 extra bytes (4000 pixels). The extra required by 1024x768 is 640 bytes (5120 pixels), and even more extra is required for larger sizes.

The linked filenames containing 'Error' generate this error in Pictview, but are displayed normal in MS Paint, Windows Photo Viewer, and Windows Live Photo Gallery. However, I did notice that Salamander's Alt-S 'thumbnail view' mode also shows the thumbnail only for the 2 icons that did not generate the error. I didn't find anything in the PNG file format saying it needed to have more image data than displays on screen.

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Joined: 23 Aug 2018, 18:39

pictview PNG not displayed correctly

Post by Maridut » 27 Aug 2018, 01:36

If you have 4GB RAM, more memory would not help. The problem is probably in PictView allocating large memory blocks. 32bit memory space is fragmented by DLLs, heaps, etc.
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