PageCopy(Source, Destination)
Copies the source video page to the destination video page.
The following is a table showing the video modes that GRAFIX supports on the Tandy 1000:
| Screen Size | Colors | Memory Required | Video Pages | Page # Range |
|---|---|---|---|---|
| 160x200 | 16 | 16K | 8 | 0-7 |
| 320x200 | 16 | 32K | 4 | 0-3 |
| 640x200 | 16 | 64K | 2 | 0-2 (Tandy 1000 SL/TL only) |
The memory required is the amount of memory needed for one graphic screen. The Tandy 1000/PCjr has the ability to access up to 128K of video memory. As you can see each graphic screen is less than 128K in size. The Tandy 1000 allows you to select which part of that 128K you want to work with as well as which part you want to display on your monitor. These graphic screens are known as video pages. You can work with one video page while displaying another. There are two types of video pages, a Display page and an Active page. The Display page is the one that shows up on your computer monitor. The Active page is the one that all the graphic functions will work with. The two do not have to be the same. You can for example work with page 1 while displaying page 0. When you initially enter any of the video modes the Active and Display pages are both set to 0. You can change these with SetActivePage and SetDisplayPage functions. The number of video pages you have to work with depends on the video mode you choose. The above table shows the maximum number of video pages for each video mode. One very important thing to remember before using video pages is that the Tandy 1000's video memory MUST first be protected. See the 'ADJMEM' section in chapter 4 for an explanation of why this must be done.
Parameters
Source - The video page to copy from.
Destination - The video page to copy to.