Color picker - slow redraw

KammutierSpule · December 2, 2020, 12:57pm

Description

I’m using a Color picker but on the screen it is used, it has a very slow redraw compared to the other widgets. It slows down all the screen redraw.
Is there any explanation for that?
Is there any way to speedup it?

What MCU/Processor/Board and compiler are you using?

STM32H7

What do you experience?

A slow redraw of the the screen when it is first displayed.

What do you expect?

Code to reproduce

Screenshot and/or video

embeddedt · December 2, 2020, 1:58pm

The color picker is a fairly slow widget in general.

github.com

lvgl/lvgl/blob/568c2ee68839005cab1d47316893fe33ea97ac77/src/lv_widgets/lv_cpicker.c#L46



#ifndef LV_CPICKER_DEF_VALUE
    #define LV_CPICKER_DEF_VALUE 100
#endif

#ifndef LV_CPICKER_DEF_HSV
    #define LV_CPICKER_DEF_HSV ((lv_color_hsv_t){LV_CPICKER_DEF_HUE, LV_CPICKER_DEF_SATURATION, LV_CPICKER_DEF_VALUE})
#endif

#ifndef LV_CPICKER_DEF_QF /*quantization factor*/
    #define LV_CPICKER_DEF_QF 3
#endif

#define TRI_OFFSET 2

/* The OUTER_MASK_WIDTH define is required to assist with the placing of a mask over the outer ring of the widget as when the
 * multicoloured radial lines are calculated for the outer ring of the widget their lengths are jittering because of the
 * integer based arithmetic. From tests the maximum delta was found to be 2 so the current value is set to 3 to achieve
 * appropriate masking.
 */
#define OUTER_MASK_WIDTH 3

You can try increasing the quantization factor; that usually increases speed at the cost of visual quality.