Improve highlighting of repainted areas

[lc-soft]

Is your feature request related to a problem? Please describe.

LCUI/src/display.c

Lines 173 to 184 in 4a9516e

	/**
	* FIXME: Improve highlighting of repainted areas
	* Let the highlighted areas disappear after a short
	* period of time, just like flashing
	*/
	if (display.show_rect_border) {
	DrawBorder(paint);
	}
	if (display.mode != LCUI_DMODE_SEAMLESS) {
	LCUICursor_Paint(paint);
	}
	Surface_EndPaint(s, paint);

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:

    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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IssueHunt Summary

vbalyasnyy has been rewarded.

Backers (Total: $10.00)

• lc-soft ($10.00)

Submitted pull Requests

• #190 feat(gui): flashing rendered rects (#180)

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[issuehunt-oss]

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[anshulxyz]

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

[issuehunt-oss]

@lc-soft has funded $5.00 to this issue.

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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 🙏

[lc-soft]

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