lv_draw.h

Defines

LV_DRAW_UNIT_NONE: Modified by NXP in 2024

LV_DRAW_UNIT_IDLE: The draw unit is idle, new dispatching might be requested to try again

Enums

enum lv_draw_task_type_t

Values:

enumerator LV_DRAW_TASK_TYPE_NONE

enumerator LV_DRAW_TASK_TYPE_FILL

enumerator LV_DRAW_TASK_TYPE_BORDER

enumerator LV_DRAW_TASK_TYPE_BOX_SHADOW

enumerator LV_DRAW_TASK_TYPE_LABEL

enumerator LV_DRAW_TASK_TYPE_IMAGE

enumerator LV_DRAW_TASK_TYPE_LAYER

enumerator LV_DRAW_TASK_TYPE_LINE

enumerator LV_DRAW_TASK_TYPE_ARC

enumerator LV_DRAW_TASK_TYPE_TRIANGLE

enumerator LV_DRAW_TASK_TYPE_MASK_RECTANGLE

enumerator LV_DRAW_TASK_TYPE_MASK_BITMAP

enumerator LV_DRAW_TASK_TYPE_VECTOR

enum lv_draw_task_state_t

Values:

enumerator LV_DRAW_TASK_STATE_WAITING

enumerator LV_DRAW_TASK_STATE_QUEUED

enumerator LV_DRAW_TASK_STATE_IN_PROGRESS

enumerator LV_DRAW_TASK_STATE_READY

Functions

void lv_draw_init(void): Used internally to initialize the drawing module

void lv_draw_deinit(void): Deinitialize the drawing module

void *lv_draw_create_unit(size_t size)

Allocate a new draw unit with the given size and appends it to the list of draw units

Parameters:: size – the size to allocate. E.g. sizeof(my_draw_unit_t), where the first element of my_draw_unit_t is lv_draw_unit_t.

lv_draw_task_t *lv_draw_add_task(lv_layer_t *layer, const lv_area_t *coords)

Add an empty draw task to the draw task list of a layer.

Parameters:

layer – pointer to a layer
coords – the coordinates of the draw task

Returns:

the created draw task which needs to be further configured e.g. by added a draw descriptor

void lv_draw_finalize_task_creation(lv_layer_t *layer, lv_draw_task_t *t)

Needs to be called when a draw task is created and configured. It will send an event about the new draw task to the widget and assign it to a draw unit.

Parameters:

layer – pointer to a layer
t – pointer to a draw task

void lv_draw_dispatch(void): Try dispatching draw tasks to draw units

bool lv_draw_dispatch_layer(lv_display_t *disp, lv_layer_t *layer)

Used internally to try dispatching draw tasks of a specific layer

Parameters:

disp – pointer to a display on which the dispatching was requested
layer – pointer to a layer

Returns:

at least one draw task is being rendered (maybe it was taken earlier)

void lv_draw_dispatch_wait_for_request(void): Wait for a new dispatch request. It's blocking if LV_USE_OS == 0 else it yields

void lv_draw_wait_for_finish(void): Wait for draw finish in case of asynchronous task execution. If LV_USE_OS == 0 it just return.

void lv_draw_dispatch_request(void): When a draw unit finished a draw task it needs to request dispatching to let LVGL assign a new draw task to it

uint32_t lv_draw_get_unit_count(void): Get the total number of draw units.

lv_draw_task_t *lv_draw_get_next_available_task(lv_layer_t *layer, lv_draw_task_t *t_prev, uint8_t draw_unit_id)

Find and available draw task

Parameters:

layer – the draw ctx to search in
t_prev – continue searching from this task
draw_unit_id – check the task where preferred_draw_unit_id equals this value or LV_DRAW_UNIT_NONE

Returns:

tan available draw task or NULL if there is no any

uint32_t lv_draw_get_dependent_count(lv_draw_task_t *t_check)

Tell how many draw task are waiting to be drawn on the area of t_check. It can be used to determine if a GPU shall combine many draw tasks into one or not. If a lot of tasks are waiting for the current ones it makes sense to draw them one-by-one to not block the dependent tasks' rendering

Parameters:: t_check – the task whose dependent tasks shall be counted
Returns:: number of tasks depending on t_check

lv_layer_t *lv_draw_layer_create(lv_layer_t *parent_layer, lv_color_format_t color_format, const lv_area_t *area)

Create (allocate) a new layer on a parent layer

Parameters:

parent_layer – the parent layer to which the layer will be merged when it's rendered
color_format – the color format of the layer
area – the areas of the layer (absolute coordinates)

Returns:

the new target_layer or NULL on error

void lv_draw_layer_init(lv_layer_t *layer, lv_layer_t *parent_layer, lv_color_format_t color_format, const lv_area_t *area)

Initialize a layer which is allocated by the user

Parameters:

layer – pointer the layer to initialize (its lifetime needs to be managed by the user)
parent_layer – the parent layer to which the layer will be merged when it's rendered
color_format – the color format of the layer
area – the areas of the layer (absolute coordinates)

Returns:

the new target_layer or NULL on error

void *lv_draw_layer_alloc_buf(lv_layer_t *layer)

Try to allocate a buffer for the layer.

Parameters:: layer – pointer to a layer
Returns:: pointer to the allocated aligned buffer or NULL on failure

void *lv_draw_layer_go_to_xy(lv_layer_t *layer, int32_t x, int32_t y)

Got to a pixel at X and Y coordinate on a layer

Parameters:

layer – pointer to a layer
x – the target X coordinate
y – the target X coordinate

Returns:

buf offset to point to the given X and Y coordinate

lv_draw_task_type_t lv_draw_task_get_type(const lv_draw_task_t *t)

Get the type of a draw task

Parameters:: t – the draw task to get the type of
Returns:: the draw task type

void *lv_draw_task_get_draw_dsc(const lv_draw_task_t *t)

Get the draw descriptor of a draw task

Parameters:: t – the draw task to get the draw descriptor of
Returns:: a void pointer to the draw descriptor

void lv_draw_task_get_area(const lv_draw_task_t *t, lv_area_t *area)

Get the draw area of a draw task

Parameters:

t – the draw task to get the draw area of
area – the destination where the draw area will be stored

struct _lv_layer_t

Public Members

lv_draw_buf_t *draw_buf: Target draw buffer of the layer

lv_area_t buf_area: The absolute coordinates of the buffer

lv_color_format_t color_format: The color format of the layer. LV_COLOR_FORMAT_...

lv_area_t _clip_area: NEVER USE IT DRAW UNITS. USED INTERNALLY DURING DRAW TASK CREATION. The current clip area with absolute coordinates, always the same or smaller than buf_area Can be set before new draw tasks are added to indicate the clip area of the draw tasks. Therefore lv_draw_add_task() always saves it in the new draw task to know the clip area when the draw task was added. During drawing the draw units also sees the saved clip_area and should use it during drawing. During drawing the layer's clip area shouldn't be used as it might be already changed for other draw tasks.