raster image of paint-stroke-207-t

Centering of stroke on the outline of rectangles.

The main indication for a failed test is the appearence of something red.

The width and position of the stroke centered on the outline of a rectangle is tested with four stroked rectangles, one is the thin black stroked test frame rectangle, the second one a large blue rectangle, the third a rectangle with rounded corners, looking like a circle and the fourth a small square.

The correct position is tested by a comparsion with several filled rectangles in the background or in the fourth case covering the test square completely. The parts of the background covered with the blue test rectangles are filled red, respectively the test square is stroked red too. Therefore if something red gets visible, the position of the stroke of the related test rectangle is wrong.

According to the conformance criteria all visual rendering should be accurate to within one px unit to the mathematically correct result. Therefore possible residuals from the red background parts have to be in this range of accuracy to pass the test.