| 摘要 |
PROBLEM TO BE SOLVED: To provide a multiscreen display unit in which overlaying processing and image processing for enlargement, reduction, etc., can be performed in a short time by reducing access to a frame buffer without making the circuit scale large. SOLUTION: The display unit is equipped with the frame buffer which is provided to store images, a memory which is provided to overlay an image, an arithmetic means which computes a transfer start address in the frame buffer and the number of transfer bytes, a mask control processing means which performs processing so that writing to a lower-layer image is not performed where the lower-layer image is not overlaid with an upper-layer image when image data in the frame buffer are written to the memory, and a data writing means which writes the image data to the memory and performs the writing in order from a low-priority image to a high-priority image. |
