1 #include "../../lv_examples.h"
2 
3 #if LV_USE_LABEL && LV_FONT_MONTSERRAT_24 && LV_USE_CANVAS && LV_BUILD_EXAMPLES && LV_DRAW_SW_COMPLEX
4 
5 #define MASK_WIDTH 150
6 #define MASK_HEIGHT 60
7 
generate_mask(lv_draw_buf_t * mask,int32_t w,int32_t h,const char * txt)8 static void generate_mask(lv_draw_buf_t * mask, int32_t w, int32_t h, const char * txt)
9 {
10     /*Create a "8 bit alpha" canvas and clear it*/
11     lv_obj_t * canvas = lv_canvas_create(lv_screen_active());
12     lv_canvas_set_draw_buf(canvas, mask);
13     lv_canvas_fill_bg(canvas, lv_color_black(), LV_OPA_TRANSP);
14 
15     lv_layer_t layer;
16     lv_canvas_init_layer(canvas, &layer);
17 
18     /*Draw a label to the canvas. The result "image" will be used as mask*/
19     lv_draw_label_dsc_t label_dsc;
20     lv_draw_label_dsc_init(&label_dsc);
21     label_dsc.color = lv_color_white();
22     label_dsc.align = LV_TEXT_ALIGN_CENTER;
23     label_dsc.text = txt;
24     label_dsc.font = &lv_font_montserrat_24;
25     lv_area_t a = {0, 0, w - 1, h - 1};
26     lv_draw_label(&layer, &label_dsc, &a);
27 
28     lv_canvas_finish_layer(canvas, &layer);
29 
30     lv_obj_delete(canvas);
31 }
32 
33 /**
34  * Draw label with gradient color
35  */
lv_example_label_4(void)36 void lv_example_label_4(void)
37 {
38     /* Create the mask of a text by drawing it to a canvas*/
39     LV_DRAW_BUF_DEFINE_STATIC(mask, MASK_WIDTH, MASK_HEIGHT, LV_COLOR_FORMAT_L8);
40     LV_DRAW_BUF_INIT_STATIC(mask);
41 
42     generate_mask(&mask, MASK_WIDTH, MASK_HEIGHT, "Text with gradient");
43 
44     /* Create an object from where the text will be masked out.
45      * Now it's a rectangle with a gradient but it could be an image too*/
46     lv_obj_t * grad = lv_obj_create(lv_screen_active());
47     lv_obj_set_size(grad, MASK_WIDTH, MASK_HEIGHT);
48     lv_obj_center(grad);
49     lv_obj_set_style_bg_color(grad, lv_color_hex(0xff0000), 0);
50     lv_obj_set_style_bg_grad_color(grad, lv_color_hex(0x0000ff), 0);
51     lv_obj_set_style_bg_grad_dir(grad, LV_GRAD_DIR_HOR, 0);
52     lv_obj_set_style_bitmap_mask_src(grad, &mask, 0);
53 }
54 
55 #endif
56