Bug 210543

Summary: [GTK] Make PlatformScreen::screenDPI() GTK4-ready
Product: WebKit Reporter: Claudio Saavedra <csaavedra>
Component: WebKitGTKAssignee: Claudio Saavedra <csaavedra>
Status: RESOLVED FIXED    
Severity: Normal CC: aperez, bugs-noreply
Priority: P2    
Version: WebKit Nightly Build   
Hardware: Unspecified   
OS: Unspecified   
Bug Depends on:    
Bug Blocks: 210100    
Attachments:
Description Flags
Patch
none
Patch for landing none

Claudio Saavedra
Reported 2020-04-15 05:44:13 PDT
[GTK] Make PlatformScreen::screenDPI() GTK4-ready
Attachments
Patch (3.30 KB, patch)
2020-04-15 05:46 PDT, Claudio Saavedra
no flags
Patch for landing (3.31 KB, patch)
2020-04-15 07:15 PDT, Claudio Saavedra
no flags
Claudio Saavedra
Comment 1 2020-04-15 05:46:28 PDT
Adrian Perez
Comment 2 2020-04-15 06:37:13 PDT
Comment on attachment 396521 [details] Patch View in context: https://bugs.webkit.org/attachment.cgi?id=396521&action=review There is just one small change needed before landing; the patch looks fine otherwise. > Source/WebCore/platform/gtk/PlatformScreenGtk.cpp:99 > + if (dpi != -1) It would be good better use “if (fabs(dpi - -1.0) > DBL_MIN)” here. Comparison of floating point values is not guaranteed to work well, I guess this has been working fine because gdk_screen_get_resolution() is doing “return -1.0” with a literal, and doing “-1 == dpi” results in comparing two doubles with the same bit-level representation… but feel free to leave it as-is if you would rather leave the existing logic untouched. > Source/WebCore/platform/gtk/PlatformScreenGtk.cpp:107 > + g_object_get(gtkSettings, "gtk-xft-dpi", &gtkXftDpi, NULL); NULL → nullptr > Source/WebCore/platform/gtk/PlatformScreenGtk.cpp:120 > + GdkMonitor* monitor = gdk_display_get_monitor(display, 0); It's a bit sad that we cannot set the DPI per web view; it would be nicer to find out on which monitor the widget is being displayed and use the value for that. Anyway, this is as good as the existing code was, so that's okay 🙆‍♂️️
Claudio Saavedra
Comment 3 2020-04-15 07:13:45 PDT
Comment on attachment 396521 [details] Patch View in context: https://bugs.webkit.org/attachment.cgi?id=396521&action=review >> Source/WebCore/platform/gtk/PlatformScreenGtk.cpp:99 >> + if (dpi != -1) > > It would be good better use “if (fabs(dpi - -1.0) > DBL_MIN)” here. Comparison > of floating point values is not guaranteed to work well, I guess this has been > working fine because gdk_screen_get_resolution() is doing “return -1.0” with a > literal, and doing “-1 == dpi” results in comparing two doubles with the same > bit-level representation… but feel free to leave it as-is if you would rather > leave the existing logic untouched. I think I'm gonna stick to the -1 comparison since we know it's a literal that's used. >> Source/WebCore/platform/gtk/PlatformScreenGtk.cpp:120 >> + GdkMonitor* monitor = gdk_display_get_monitor(display, 0); > > It's a bit sad that we cannot set the DPI per web view; it would be nicer to > find out on which monitor the widget is being displayed and use the value for > that. Anyway, this is as good as the existing code was, so that's okay 🙆‍♂️️ We can check whether doing this would be feasible when we break API for GTK4, but this code will have to move somewhere else as PlatformScreen is not useful with multiple monitors.
Claudio Saavedra
Comment 4 2020-04-15 07:15:25 PDT
Created attachment 396530 [details] Patch for landing
EWS
Comment 5 2020-04-15 07:54:57 PDT
Committed r260127: <https://trac.webkit.org/changeset/260127> All reviewed patches have been landed. Closing bug and clearing flags on attachment 396530 [details].
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