Efficient scaling of image data in graphics display systems
In a preferred embodiment, a system includes a host, an image data source, and a graphics controller. The image data source provides a frame corresponding to a particular image size. The graphics controller is receives the frame. Preferably, the graphics controller is remote from the image data source and the host, and includes a fitting module for calculating a scale factor based on the image size, and a scaling unit for scaling the image according to the scale factor. In another preferred embodiment, a system includes a display device of a particular resolution, a memory, and a graphics controller. The memory is for storing a frame corresponding to a particular image size. The graphics controller preferably includes: a fitting module for calculating a scale factor based on the image size and the display device resolution, and a scaling unit for scaling the image according to the scale factor. The graphics controller may be adapted for retrieving the display device resolution from the display device. Preferred embodiments prevent the host from being repeatedly interrupted each time a new frame needs to be stored or written to the display device thereby improving host and system efficiency.
1. A graphics display system, comprising:
a host to provide at least one parameter specifying an image size of a frame of pixels corresponding to an original image;
an image data source to provide the original image; and
a graphics controller to receive the frame corresponding with the original image from the image data source, the graphics controller being remote from the image data source and the host, and including:
(a) a memory of a particular size to store a scaled frame;
(b) a register to store the size of a portion of the memory allocated to store the scaled frame;
(c) a fitting module to receive the at least one image size parameter from the host and to calculate a scale factor based on the original image size and the size of the portion of the memory allocated to store the scaled frame, wherein the register is only accessible by the fitting module, and
(d) a scaling unit to scale the original image according to the scale factor.
2. The system of claim 1 , wherein the portion of the memory allocated to store the scaled frame is one of at least two different sizes.
3. The system of claim 1 , wherein the scaling unit down-scales the image for storing in the memory.
4. The system of claim 1 , wherein the host and the image data source are remote from each other.
5. The system of claim 1 , wherein the image data source is a camera.
6. The system of claim 1 , wherein the fitting module is additionally to issue a query to and receive from the image data source the at least one image size parameter.
7. A graphics controller for interfacing a host and an image data source, comprising:
(a) a memory having allocable memory capacity to store a scaled frame of pixels;
(b) a register to store an original image size parameter, the original image size parameter corresponding with an original image;
(c) a register to store a scaled image size parameter;
(d) a fitting module to calculate a scale factor based on the original image size parameter and the scaled image size parameter; and
(e) a scaling unit to scale the original image according to the scale factor, wherein the graphics controller is remote from the image data source and the host, and wherein the scaled image size parameter corresponds with the size of the portion of the memory allocated to the scaled frame.
8. The graphics controller of claim 7 , wherein the fitting module is additionally to issue a query to the host and to receive from the host the original image size parameter.
9. The graphics controller of claim 7 , wherein the fitting module is additionally to issue a query to the image data source and to receive from the image data source the original image size parameter.
10. The graphics controller of claim 7 , wherein the fitting module is additionally to determine the size of the portion of the memory allocated to store a frame and thereby determine the scaled image size parameter.