Hello, A few days ago I was trying out Adobe Photoshop CS4 under my OS, Windows 7 RC 64 bit, and although I prefer using GIMP even though it lacks some very useful features, I was surprised at one thing in particular: its speed when many layers are used (20-25+, and on very complex works I often use even more). On Photoshop CS4 layers refresh almost instantly, new ones are created with about the same speed, and there are generally no graphic slowdowns on complex works.
At some point I tried to save my work done under Photoshop and import it in GIMP. I discovered that all layers were cropped to their maximum extents (empty borders taken out). I thought that this could be one of the main reasons why Photoshop is faster when many layers are used: since unused borders are taken out, there's less to redraw to the screen each time or to check out for transparency. I'm not sure though if this is done by GIMP during the import process or in a transparent way (when a new layer is created it's assumed that it will cover the whole canvas) automatically in Photoshop, though. To verify my claim I tried to make a similarly complex, multilayered work natively under GIMP 2.6.6 (canvas size A4, 300 dpi, about 3500x2500 pixels) until at some point I reached about 25 different layers. Of course the program was still usable, but some slowdown was evident especially when toggling layer visibility (operation which took a while to complete). I then applied my so-called "Photoshop optimization" by autocropping all layers (Menu Layer>Autocrop), and working speed went up noticeably, though not dramatically (note that I'm using an Intel Core 2 Duo 3.16 Ghz E8500 processor with 4 GB RAM). What I wonder is if GIMP could someday get advantage dynamically, automatically and in a transparent manner to the user of autocropping extra borders from layers (without manual intervention) in order improve performance when large canvases and many layers (the normality in creative works, not so much when only retouching photos) are used. For example, the user would create a 3500x2500 pixels new layer, but if he drew only in a small 100x200 pixels area, then the program would internally save and process only that area, while still allowing the user to draw outside of it (the layer extents would be automatically and transparently increased). What do you think about this proposition? -- SHIRAKAWA Akira _______________________________________________ Gimp-developer mailing list Gimp-developer@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-developer
