| 摘要 |
PURPOSE:To perform graphic drawing and clipping processing at a high speed by informing the recognition of boundary of a view port to a graphic signal generating means with an interruption. CONSTITUTION:A graphic signal generating means 1 reads the view port information given from outside as well as both the start and end points of a graphic to be displayed and then sets the view port information to a comparator 2. At the same time, the means 1 produces the spot train signals forming a straight line from the given start/end point information and sets them to the comparator 2. The comparator 2 compares the view port information with the spot train signal and performs writing into a drawing memory 3 if the corresponding spot is set within the view port. Then the comparator 2 applies an interruption to the means 1 to inform the recognition of boundary to the means 1 when the front one of adjacent spots is set within the viewport range with the rear spot set outside said range respectively. |
