Bitmaps and Fonts can be located in external memory. To refer the data, EXTDATA structure is used:
typedef struct _EXTDATA_ { TYPE_MEMORY type; // must be set to EXTERNAL WORD ID; // memory ID DWORD address; // bitmap or font image address } EXTDATA;
where:
- type – shows type of memory used.
- 0 – internal
- 1 - external.
- ID – unique number must be assigned by application to have a way distinguishing memory chips if the application has several of them.
- address – start address of the bitmap or font image in the external memory.
This function must be implemented in the application. Inside, the application must copy requested bytes quantity into the buffer provided. Data start address can be calculated as a sum of the start image address specified in EXTDATA structure and offset provided.
Functions
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This function must be implemented in the application. The library will call this function each time when the external memory data will be required. The application must copy requested bytes quantity into the buffer provided. Data start address in external memory is a sum of the address in GFX_EXTDATA structure and offset. |
Macros
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This defines the size of the buffer used by font functions to retrieve font data from the external memory. The buffer size can be increased to accommodate large font sizes. The user must be aware of the expected glyph sizes of the characters stored in the font table. To modify the size used, declare this macro in the GraphicsConfig.h file with the desired size. |
Topics
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Memory type enumeration to determine the source of data. Used in interpreting bitmap and font from different memory sources. |
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