Standardization of graphics system logical frame buffer

摘要

A method for implementing a bitmapped graphics system involves creating a logical frame buffer for a program. The method attaches a standardization operation to the logical frame buffer, so that the standardization operation is automatically executed upon the invocation of draw function by an application. The standardization operation serves to perform all of the functions required to properly transmit the contents of the logical frame buffer into the hardware frame buffer, arbitrates access to the logical frame buffer, if necessary, and performs other useful logical operations. In the preferred embodiment, the standardization operation comprises a complementary pre-process and a post-process. The pre-process is invoked prior to the execution of a graphics system draw operation, while the post-process is invoked thereafter. The pre-process and post-process may include more than one distinct pre-function and post-function. The post-functions are executed in last-in-first-out order relative to their order of operations, while the pre-functions are executed in first-in-first-out order relative to their order of operations. According to another aspect, a device executes an application draw function using the above-described uniform, standardized graphic system. A complementary pre-process and post-process removes the complexity of dealing with hiding the cursor prior to drawing into the frame buffer and showing the cursor after drawing into the frame buffer. Another example involves handling communication peculiarities, such as transporting the contents of the logical frame buffer across a parallel port to a hardware frame buffer which is not directly addressable by the processor. Yet another example involves logical frame buffer rotation to counteract peculiar rotation states wired into the hardware frame buffer. Still another example involves arbitrating access to a logical frame buffer which is accessible by more than one application.