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docs(calvas): fix that LV_CANVAS_BUF_SIZE_ return byte count and not pixel count

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fixes #3734
This commit is contained in:
Gabor Kiss-Vamosi 2022-10-11 20:17:11 +02:00
parent 5971894a9b
commit 853163f615
3 changed files with 4 additions and 5 deletions
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2
docs/widgets/canvas.md
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@ -18,7 +18,7 @@ The Canvas needs a buffer in which stores the drawn image.
To assign a buffer to a Canvas, use `lv_canvas_set_buffer(canvas, buffer, width, height, LV_IMG_CF_...)`.
Where `buffer` is a static buffer (not just a local variable) to hold the image of the canvas.
For example,
`static lv_color_t buffer[LV_CANVAS_BUF_SIZE_TRUE_COLOR(width, height)]`.
`static uint8_t buffer[LV_CANVAS_BUF_SIZE_TRUE_COLOR(width, height)]`.
`LV_CANVAS_BUF_SIZE_...` macros help to determine the size of the buffer with different color formats.
The canvas supports all the built-in color formats like `LV_IMG_CF_TRUE_COLOR` or `LV_IMG_CF_INDEXED_2BIT`.

4
examples/widgets/canvas/lv_example_canvas_1.c
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@ -25,7 +25,7 @@ void lv_example_canvas_1(void)
lv_draw_label_dsc_init(&label_dsc);
label_dsc.color = lv_palette_main(LV_PALETTE_ORANGE);
static lv_color_t cbuf[LV_CANVAS_BUF_SIZE_TRUE_COLOR(CANVAS_WIDTH, CANVAS_HEIGHT)];
static uint8_t cbuf[LV_CANVAS_BUF_SIZE_TRUE_COLOR(CANVAS_WIDTH, CANVAS_HEIGHT)];
lv_obj_t * canvas = lv_canvas_create(lv_scr_act());
lv_canvas_set_buffer(canvas, cbuf, CANVAS_WIDTH, CANVAS_HEIGHT, LV_IMG_CF_TRUE_COLOR);
@ -38,7 +38,7 @@ void lv_example_canvas_1(void)
/*Test the rotation. It requires another buffer where the original image is stored.
*So copy the current image to buffer and rotate it to the canvas*/
static lv_color_t cbuf_tmp[CANVAS_WIDTH * CANVAS_HEIGHT];
static uint8_t cbuf_tmp[LV_CANVAS_BUF_SIZE_TRUE_COLOR(CANVAS_WIDTH, CANVAS_HEIGHT)];
memcpy(cbuf_tmp, cbuf, sizeof(cbuf_tmp));
lv_img_dsc_t img;
img.data = (void *)cbuf_tmp;

3
examples/widgets/canvas/lv_example_canvas_2.c
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@ -13,7 +13,7 @@ void lv_example_canvas_2(void)
lv_btn_create(lv_scr_act());
/*Create a buffer for the canvas*/
static lv_color_t cbuf[LV_CANVAS_BUF_SIZE_INDEXED_1BIT(CANVAS_WIDTH, CANVAS_HEIGHT)];
static uint8_t cbuf[LV_CANVAS_BUF_SIZE_INDEXED_1BIT(CANVAS_WIDTH, CANVAS_HEIGHT)];
/*Create a canvas and initialize its palette*/
lv_obj_t * canvas = lv_canvas_create(lv_scr_act());
@ -39,6 +39,5 @@ void lv_example_canvas_2(void)
lv_canvas_set_px_color(canvas, x, y, c0);
}
}
}
#endif