GAL: zoom-out loses position at high resolution

[Chris Pavlina]

With a large window size (here maximized on a 3840x2160 display, giving a window size of 3832x2087), when zooming out in GAL (including both OpenGL and Cairo) the position is lost and jumps around horribly. I centered my display with Home, placed the cursor in the middle, then zoomed out with F2 to avoid accidentally moving the cursor, and quickly ended up several hundred millimeters off the border. This does not happen with a smaller window size (for example, at 1843x1307).

Application: kicad
Version: (2018-01-04 revision 658d181ec)-master, release build
Libraries:
    wxWidgets 3.0.3
    libcurl/7.57.0 OpenSSL/1.1.0g zlib/1.2.11 libidn2/2.0.4 libpsl/0.19.1 (+libidn2/2.0.4) libssh2/1.8.0 nghttp2/1.28.0
Platform: Linux 4.14.10-1-ARCH x86_64, 64 bit, Little endian, wxGTK
Build Info:
    wxWidgets: 3.0.3 (wchar_t,wx containers,compatible with 2.8) GTK+ 2.24
    Boost: 1.65.1
    Curl: 7.57.0
    Compiler: GCC 7.2.1 with C++ ABI 1011

Build settings:
    USE_WX_GRAPHICS_CONTEXT=OFF
    USE_WX_OVERLAY=OFF
    KICAD_SCRIPTING=ON
    KICAD_SCRIPTING_MODULES=ON
    KICAD_SCRIPTING_WXPYTHON=ON
    KICAD_SCRIPTING_ACTION_MENU=OFF
    BUILD_GITHUB_PLUGIN=ON
    KICAD_USE_OCE=ON
    KICAD_SPICE=ON

[Chris Pavlina (pavlina-chris)]

Update - I just noticed that when this happens, I'm also able to zoom out so far that rendering just _stops_. I can manually pan back to center, but if I don't zoom in a bit, the board doesn't show up at all - even though I only need to zoom back in a couple steps to see it (so it's not just too small to see).

[Oivind Toien (otoien)]

While zoom out could *appear* to work OK on latest Windows nightly (2018-01-04 revision 658d181ec), 1080x1920 screen size, when zoom level gets very low (very small size, usually unpractical at this resolution) mouse steady centered in the middle of the board, during the last few zoom out steps with the mouse wheel, the board suddenly starts jumping vertically and eventually off the visible area. Z in the status bar (I assume that designates zoom level) is then at 0.3 when this happens and does not change further while board size still gets a bit smaller after a few wheel steps. Thus the bug is confirmed.

While this would not seem too bothersome, I have a problem when I accidentally press the wheel of my MS comfort mouse too to far (actually causes a push of the wheel sideways to the left) it will effect this quick uncontrolled zoom out until it the board goes off the screen so that I need to go hunting for it to find it again. So it certainly would be nice to have this bug fixed because of that in spite of zoom levels that can seem impractically small.

Application: kicad
Version: (2018-01-04 revision 658d181ec)-makepkg, release build
Libraries:
    wxWidgets 3.0.3
    libcurl/7.54.1 OpenSSL/1.0.2l zlib/1.2.11 libssh2/1.8.0 nghttp2/1.23.1 librtmp/2.3
Platform: Windows 7 (build 7601, Service Pack 1), 64-bit edition, 64 bit, Little endian, wxMSW
Build Info:
    wxWidgets: 3.0.3 (wchar_t,wx containers,compatible with 2.8)
    Boost: 1.60.0
    Curl: 7.54.1
    Compiler: GCC 7.1.0 with C++ ABI 1011

Build settings:
    USE_WX_GRAPHICS_CONTEXT=OFF
    USE_WX_OVERLAY=OFF
    KICAD_SCRIPTING=ON
    KICAD_SCRIPTING_MODULES=ON
    KICAD_SCRIPTING_WXPYTHON=ON
    KICAD_SCRIPTING_ACTION_MENU=ON
    BUILD_GITHUB_PLUGIN=ON
    KICAD_USE_OCE=ON
    KICAD_SPICE=ON

[Oivind Toien (otoien)]

Added comment: I tried Using F2 to zoom out and with the same nightly as above. That does not cause this problem, it stops at 0.3 not only in number, but also in size and does not jump (provided mouse cursor is left in the center). So I can only confirm the bug when mouse (wheel) is used to zoom out, intentionally or accidentally.

[Seth Hillbrand (sethh)]

Seems to be fixed in current master