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#include "../../lv_examples.h"
#if LV_USE_ROLLER && LV_DRAW_SW_COMPLEX && LV_BUILD_EXAMPLES && 1
static void generate_mask(lv_draw_buf_t * mask)
{
/*Create a "8 bit alpha" canvas and clear it*/
lv_obj_t * canvas = lv_canvas_create(lv_screen_active());
lv_canvas_set_draw_buf(canvas, mask);
lv_canvas_fill_bg(canvas, lv_color_white(), LV_OPA_TRANSP);
lv_layer_t layer;
lv_canvas_init_layer(canvas, &layer);
/*Draw a label to the canvas. The result "image" will be used as mask*/
lv_draw_rect_dsc_t rect_dsc;
lv_draw_rect_dsc_init(&rect_dsc);
rect_dsc.bg_grad.dir = LV_GRAD_DIR_VER;
rect_dsc.bg_grad.stops[0].color = lv_color_black();
rect_dsc.bg_grad.stops[1].color = lv_color_white();
rect_dsc.bg_grad.stops[0].opa = LV_OPA_COVER;
rect_dsc.bg_grad.stops[1].opa = LV_OPA_COVER;
lv_area_t a = {0, 0, mask->header.w - 1, mask->header.h / 2 - 10};
lv_draw_rect(&layer, &rect_dsc, &a);
a.y1 = mask->header.h / 2 + 10;
a.y2 = mask->header.h - 1;
rect_dsc.bg_grad.stops[0].color = lv_color_white();
rect_dsc.bg_grad.stops[1].color = lv_color_black();
lv_draw_rect(&layer, &rect_dsc, &a);
lv_canvas_finish_layer(canvas, &layer);
/*Comment it to make the mask visible*/
lv_obj_delete(canvas);
}
/**
* Add a fade mask to roller.
*/
void lv_example_roller_3(void)
{
lv_obj_set_style_bg_color(lv_screen_active(), lv_palette_main(LV_PALETTE_BLUE_GREY), 0);
static lv_style_t style;
lv_style_init(&style);
lv_style_set_bg_color(&style, lv_color_black());
lv_style_set_text_color(&style, lv_color_white());
lv_style_set_border_width(&style, 0);
lv_style_set_radius(&style, 0);
lv_obj_t * roller1 = lv_roller_create(lv_screen_active());
lv_obj_add_style(roller1, &style, 0);
lv_obj_set_style_bg_opa(roller1, LV_OPA_50, LV_PART_SELECTED);
lv_roller_set_options(roller1,
"January\n"
"February\n"
"March\n"
"April\n"
"May\n"
"June\n"
"July\n"
"August\n"
"September\n"
"October\n"
"November\n"
"December",
LV_ROLLER_MODE_NORMAL);
lv_obj_center(roller1);
lv_roller_set_visible_row_count(roller1, 4);
/* Create the mask to make the top and bottom part of roller faded.
* The width and height are empirical values for simplicity*/
LV_DRAW_BUF_DEFINE_STATIC(mask, 130, 150, LV_COLOR_FORMAT_L8);
LV_DRAW_BUF_INIT_STATIC(mask);
generate_mask(&mask);
lv_obj_set_style_bitmap_mask_src(roller1, &mask, 0);
}
#endif
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