Improve highlighting of repainted areas

[lc-soft]

Is your feature request related to a problem? Please describe. https://github.com/lc-soft/LCUI/blob/4a9516e8eb3bc23b681575653ac31468093d8a2c/src/display.c#L173-L184

Describe the solution you'd like

Remove DrawBorder() function and use FlashPaintArea() instead, this function should do the following:

• Save the repainting area and its paint time into a list.

  record.rect = paint_rect;
  record.paint_time = clock();
  LinkedList_Append(&list, &record);

• Create a timer to repaint each highlighted area of the list every 10 milliseconds.

  int timer = LCUI_SetInterval(10, OnUpdateHighlightArea, NULL);

• Check the paint time of the highlighted area:

  if (clock() - record.paint_time >= duration) {
      // remove record and get next area.
  }

• Fill the repainted area with the corresponding transparency color based on the current time:

  • Create a bitmap named mask:

    
    LCUI_Graph mask;

  Graph_Init(&mask); mask.color_type = LCUI_COLOR_TYPE_ARGB; Graph_Create(&mask, record.rect.width, record.rect.height);

  - Fill color into `mask`:
  ```c
  Graph_FillRect(&mask, NULL, RGBA(255, 0, 0, 200), TRUE);

  • Paint a border to the mask. Refer the DrawBorder() function
  • Compute mask opacity:

    mask.opactiy = 1.0 * (record.paint_time + duration - clock()) / duration;

  • Render the original content of the painting area and blend mask into the canvas:

    paint = Surface_BeginPaint(s, paint_rect);
    Widget_Render(record->widget, paint);
    Graph_Mix(&paint->canvas, &mask);
    Surface_EndPaint(s, paint);

The final effect should be the same as the paint flashing of Google Chrome:

Describe alternatives you've considered None.

Additional context None.

---

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[anshulxyz]

hi, @lc-soft can you describe further what you mean by "improve" the highlighting, can you show some examples?

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[anshulxyz]

@lc-soft do you have any design/style in mind?

[lc-soft]

@anshulxyz This is a low priority task and I will update the description as soon as possible.

[anshulxyz]

Alright :pray:

[lc-soft]

@anshulxyz The issue description has been updated. Maybe the implementation of this feature is a bit complicated.

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