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POLeaving a data array (Font) in FLASH - PROGMEM in AVR GCC
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copied!<p>Ahhh, PROGMEM, pointers, pointers to pointers, addresses of pointers... My head boggles.</p> <p>I have a data array for the font in question</p> <pre><code>const uint8_t dejaVuSans9ptBitmaps[] = { /* @0 ' ' (5 pixels wide) */ 0x00, /* */ 0x00, /* */ ... </code></pre> <p>to which I have added PROGMEM</p> <pre><code>const uint8_t dejaVuSans9ptBitmaps[] PROGMEM = </code></pre> <p>This is referenced in another structure like so;</p> <pre><code>const FONT_INFO dejaVuSans9ptFontInfo = { 13, ' ', '~', dejaVuSans9ptDescriptors, dejaVuSans9ptBitmaps, }; </code></pre> <p>The structure is defined as;</p> <pre><code>typedef struct { const uint8_t height; const uint8_t startChar; const uint8_t endChar; const FONT_CHAR_INFO* charInfo; const uint8_t* data; } FONT_INFO; </code></pre> <p>Am I correct in assuming this needs to change to;</p> <pre><code>typedef struct { const uint8_t height; const uint8_t startChar; const uint8_t endChar; const FONT_CHAR_INFO* charInfo; const PGM_P data; } FONT_INFO; </code></pre> <p>When I do so, it complains that </p> <pre><code>warning: pointer targets in initialization differ in signedness </code></pre> <p>For this particular line in the FONT_INFO variable;</p> <pre><code>const FONT_INFO dejaVuSans9ptFontInfo = { 13, ' ', '~', dejaVuSans9ptDescriptors, --> dejaVuSans9ptBitmaps, <-- }; </code></pre> <p>It is then drawn using the function;</p> <pre><code>void drawString(uint16_t x, uint16_t y, uint16_t color, const FONT_INFO *fontInfo, char *str) { ... drawCharBitmap(currentX, y, color, &fontInfo->data[charOffset], charWidth, fontInfo->height); ... </code></pre> <p>Which finally draws the glyph;</p> <pre><code>void drawCharBitmap(const uint16_t xPixel, const uint16_t yPixel, uint16_t color, const uint8_t *glyph, uint8_t cols, uint8_t rows) { ... if (glyph[indexIntoGlyph] & (0X80)) drawPixel(currentX, currentY, color); ... </code></pre> <p>I am in over my head :/ Can anyone give me some direction? I have spent hours trying to use PGM_P, and pgm_read_byte etc to no avail - I always get garbage on the screen.</p> <p>Save me!</p>

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