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- /*
- Another example adapted from ugfx http://ugfx.org
- This actually shows a problem of RA8875 library, writing
- one pixel it's fast but write many single pixels in the same time
- not and speed suffer.
- It shoul be a workaround that I'm actually study, this will fix
- also loading big images from SD memory card and so on.
- */
- #include <SPI.h>
- #include <RA8875.h>
-
-
- #define RA8875_CS 10
-
- #define RA8875_RESET 9//any pin or nothing!
-
- RA8875 tft = RA8875(RA8875_CS, RA8875_RESET);
-
-
-
- const int MAX = 256;
- float cx, cy;
- float zoom = 1.0f;
-
- void setup()
- {
- Serial.begin(9600);
- //while (!Serial) {;}
- Serial.println("RA8875 start");
-
- tft.begin(RA8875_800x480);
-
- cx = -0.086f;
- cy = 0.85f;
- }
-
-
- void loop()
- {
- mandelbrot(-2.0f * zoom + cx, -1.5f * zoom + cy, 2.0f * zoom + cx, 1.5f * zoom + cy);
- zoom *= 0.7f;
- if (zoom <= 0.00001f)
- zoom = 1.0f;
- }
-
- void mandelbrot(float x1, float y1, float x2, float y2) {
- unsigned int i, j;
- uint16_t iter;
- uint16_t color;
-
- float sy = y2 - y1;
- float sx = x2 - x1;
-
- for (i = 0; i < tft.width(); i++) {
- for (j = 0; j < tft.height(); j++) {
- float cy = j * sy / tft.height() + y1;
- float cx = i * sx / tft.width() + x1;
- float x = 0.0f, y = 0.0f, xx = 0.0f, yy = 0.0f;
- for (iter = 0; iter <= MAX && (xx + yy) < 4.0f; iter++) {
- xx = x * x;
- yy = y * y;
- y = 2.0f * x * y + cy;
- x = xx - yy + cx;
- }
- color = ((iter << 7 & 0xF8) << 8) | ((iter << 4 & 0xFC) << 3) | (iter >> 3);
- tft.drawPixel(i, j, color);
- }
- }
- }
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