45 lines
1.3 KiB
C
45 lines
1.3 KiB
C
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#include "../../lv_examples.h"
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#if LV_USE_CANVAS && LV_BUILD_EXAMPLES
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#define CANVAS_WIDTH 50
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#define CANVAS_HEIGHT 50
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/**
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* Create a transparent canvas with Chroma keying and indexed color format (palette).
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*/
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void lv_example_canvas_2(void)
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{
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/*Create a button to better see the transparency*/
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lv_btn_create(lv_scr_act());
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/*Create a buffer for the canvas*/
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static lv_color_t cbuf[LV_CANVAS_BUF_SIZE_INDEXED_1BIT(CANVAS_WIDTH, CANVAS_HEIGHT)];
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/*Create a canvas and initialize its palette*/
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lv_obj_t * canvas = lv_canvas_create(lv_scr_act());
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lv_canvas_set_buffer(canvas, cbuf, CANVAS_WIDTH, CANVAS_HEIGHT, LV_IMG_CF_INDEXED_1BIT);
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lv_canvas_set_palette(canvas, 0, LV_COLOR_CHROMA_KEY);
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lv_canvas_set_palette(canvas, 1, lv_palette_main(LV_PALETTE_RED));
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/*Create colors with the indices of the palette*/
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lv_color_t c0;
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lv_color_t c1;
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c0.full = 0;
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c1.full = 1;
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/*Red background (There is no dedicated alpha channel in indexed images so LV_OPA_COVER is ignored)*/
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lv_canvas_fill_bg(canvas, c1, LV_OPA_COVER);
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/*Create hole on the canvas*/
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uint32_t x;
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uint32_t y;
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for(y = 10; y < 30; y++) {
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for(x = 5; x < 20; x++) {
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lv_canvas_set_px_color(canvas, x, y, c0);
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}
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}
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}
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#endif
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