Drawing functions pass individual drawing orders to the graphics engine. The graphics engine then draws, correlates, and takes, or takes bounds on, the drawing primitives as directed by the flags. The graphics engine is assumed to clip to the appropriate part of the window, which is the region excluding any window border or frills.
Coordinates are passed as signed 32-bit numbers in a logical space called "world-coordinate space". Angles are also passed as signed 32-bit numbers. Zero refers to the direction of the positive X-axis; 2(31st power) represents 360ø. Positive values are counterclockwise from the positive X-axis.