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| projects:ui-scaling [2023/01/02 10:52] – [Basics] kelnos | projects:ui-scaling [2023/01/02 11:07] (current) – [Things that work] kelnos |
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| * If you don't even have a window, you can use ''gdk_monitor_get_scale_factor()''. | * If you don't even have a window, you can use ''gdk_monitor_get_scale_factor()''. |
| * Scale factors are (unfortunately) integer-only. There's no such thing as a 1.5x scale, for example. | * Scale factors are (unfortunately) integer-only. There's no such thing as a 1.5x scale, for example. |
| * You can connect to ''notify::scale-factor'' on a `GtkWidget` or `GdkMonitor` instance to know when you might need to reload icons at a new scale factor. | * You can connect to ''notify::scale-factor'' on a ''GtkWidget'' or ''GdkMonitor'' instance to know when you might need to reload icons at a new scale factor. |
| ===== Things that work ===== | ===== Things that work ===== |
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| * Any manually-loaded ''GdkPixbuf'' instances should be loaded at a width and height multiplied by the scale factor. Then, "wrap" the pixbuf in a ''cairo_surface_t'' using ''gdk_cairo_surface_create_from_pixbuf()'', which takes the scale factor. It can also take a ''GdkWindow'', but it's fine to pass ''NULL'' there. | * Any manually-loaded ''GdkPixbuf'' instances should be loaded at a width and height multiplied by the scale factor. Then, "wrap" the pixbuf in a ''cairo_surface_t'' using ''gdk_cairo_surface_create_from_pixbuf()'', which takes the scale factor. It can also take a ''GdkWindow'', but it's fine to pass ''NULL'' there. |
| * When loading themed icons, use the ''_for_scale()'' variants: ''gtk_icon_theme_lookup_icon_for_scale()'', ''gtk_icon_theme_load_icon_for_scale()'', and ''gtk_icon_theme_lookup_gicon_for_scale()''. Pass the unscaled size for the ''size'' parameter, and the UI scale factor for the ''scale'' parameter. I also recommend passing ''GTK_ICON_LOOKUP_FORCE_SIZE''. | * When loading themed icons, use the ''_for_scale()'' variants: ''gtk_icon_theme_lookup_icon_for_scale()'', ''gtk_icon_theme_load_icon_for_scale()'', and ''gtk_icon_theme_lookup_by_gicon_for_scale()''. Pass the unscaled size for the ''size'' parameter, and the UI scale factor for the ''scale'' parameter. I also recommend passing ''GTK_ICON_LOOKUP_FORCE_SIZE''. |
| * ''GIcon'' is a useful alternative in cases where it's awkward to pass around a scale factor (for example, in a ''GtkTreeModel'' implementation, the model shouldn't really know "view" details like the UI scale factor). ''GIcon'' has quite a few implementation types, like ''GFileIcon'', ''GThemedIcon'', and ''GEmblemedIcon''. Even ''GdkPixbuf'' implements ''GIcon''. There's also ''GLoadableIcon'', which you can fairly easily implement if you need to do something custom. | * ''GIcon'' is a useful alternative in cases where it's awkward to pass around a scale factor (for example, in a ''GtkTreeModel'' implementation, the model shouldn't really know "view" details like the UI scale factor). ''GIcon'' has quite a few implementation types, like ''GFileIcon'', ''GThemedIcon'', and ''GEmblemedIcon''. Even ''GdkPixbuf'' implements ''GIcon''. There's also ''GLoadableIcon'', which you can fairly easily implement if you need to do something custom. |
| * If using ''GIcon'' with ''GtkImage'', you can get arbitrary sizing (that is, other sizes beyond what ''GTK_ICON_SIZE_'' offers) by using ''gtk_image_set_pixel_size()''. The code in ''GtkImage'' ignores the ''GTK_ICON_SIZE_'' sizes if the pixel size is specified. For the pixel size, you want to specify the unscaled size. | * If using ''GIcon'' with ''GtkImage'', you can get arbitrary sizing (that is, other sizes beyond what ''GTK_ICON_SIZE_'' offers) by using ''gtk_image_set_pixel_size()''. The code in ''GtkImage'' ignores the ''GTK_ICON_SIZE_'' sizes if the pixel size is specified. For the pixel size, you want to specify the unscaled size. |