All coordinate systems in GTK have the origin at the top left, with the X axis
pointing right, and the Y axis pointing down. This matches the convention used
in X11, Wayland and cairo, but differs from OpenGL and PostScript, where the origin
-is in the lower left, and the Y axis is pointin up.
+is in the lower left, and the Y axis is pointing up.
Every widget in a window has its own coordinate system that it uses to place its
child widgets and to interpret events. Most of the time, this fact can be safely
parent's coordinate system.
Note that the **_text direction_** of a widget does not influence its coordinate
-systems, but simply determines whether text flows in the direction of increasing
-or decreasing Y coordinates.
+system, but simply determines whether text flows in the direction of increasing
+or decreasing X coordinates.
## Events