lv_canvas.h

API reference for lv_canvas.h

Summary

Set a draw buffer for the canvas. A draw buffer either can be allocated by lv_draw_buf_create() or defined statically by LV_DRAW_BUF_DEFINE_STATIC. When buffer start address and stride has alignment requirement, it's recommended to use lv_draw_buf_create.

void lv_canvas_set_draw_buf(lv_obj_t *obj, lv_draw_buf_t *draw_buf)

Name	Type	Description
`obj`	`lv_obj_t *`	pointer to a canvas object
`draw_buf`	`lv_draw_buf_t *`	pointer to a draw buffer

widgets/canvas/lv_canvas.h:89function

lv_canvas_set_px

Set a pixel's color and opacity

void lv_canvas_set_px(lv_obj_t *obj, int32_t x, int32_t y, lv_color_t color, lv_opa_t opa)

Name	Type	Description
`obj`	`lv_obj_t *`	pointer to a canvas
`x`	`int32_t`	X coordinate of the pixel
`y`	`int32_t`	Y coordinate of the pixel
`color`	`lv_color_t`	the color
`opa`	`lv_opa_t`	the opacity

The following color formats are supported LV_COLOR_FORMAT_I1/2/4/8, LV_COLOR_FORMAT_A8, LV_COLOR_FORMAT_RGB565, LV_COLOR_FORMAT_RGB888, LV_COLOR_FORMAT_XRGB8888, LV_COLOR_FORMAT_ARGB8888

this function invalidates the canvas object every time, for best performance, if you're changing a lot of pixels in a loop, call lv_display_enable_invalidation before the loop starts so the invalidation isn't done on every call

widgets/canvas/lv_canvas.h:101function

lv_canvas_set_palette

Set the palette color of a canvas for index format. Valid only for LV_COLOR_FORMAT_I1/2/4/8

void lv_canvas_set_palette(lv_obj_t *obj, uint8_t index, lv_color32_t color)

Name	Type	Description
`obj`	`lv_obj_t *`	pointer to canvas object
`index`	`uint8_t`	the palette color to set: - for `LV_COLOR_FORMAT_I1`: 0..1 - for `LV_COLOR_FORMAT_I2`: 0..3 - for `LV_COLOR_FORMAT_I4`: 0..15 - for `LV_COLOR_FORMAT_I8`: 0..255
`color`	`lv_color32_t`	the color to set

Macros

widgets/canvas/lv_canvas.h:178macro

LV_CANVAS_BUF_SIZE

#define LV_CANVAS_BUF_SIZE(w, h, bpp, stride) \
    (((((w * bpp + 7) >> 3) + stride - 1) & ~(stride - 1)) * h + LV_DRAW_BUF_ALIGN)

Variables

widgets/canvas/lv_canvas.h:30variable

lv_canvas_class

const lv_obj_class_t lv_canvas_class

Dependencies

Indirect dependencies

Name	Type	Description
`obj`	`lv_obj_t *`	pointer to a canvas object
`buf`	`void *`	buffer where content of canvas will be. The required size is (lv_image_color_format_get_px_size(cf) * w) / 8 * h) It can be allocated with `lv_malloc()` or it can be statically allocated array (e.g. static `lv_color_t` buf[100*50]) or it can be an address in RAM or external SRAM
`w`	`int32_t`	width of canvas
`h`	`int32_t`	height of canvas
`cf`	`lv_color_format_t`	color format. `LV_COLOR_FORMAT...`

lv_canvas.h

Functions

lv_canvas_set_buffer

lv_canvas_set_draw_buf