WM Transparent Windows (Sample)

WM_TransparentWindows.c
File(s) required	WM_TransparentWindows.c
Runs in simulation	Yes
Runs on target	Yes
Download	WM_TransparentWindows.c

This sample demonstrates how transparent windows can be created. It also shows how semi-transparent drawing operations are performed in a transparent window.

Code

/*********************************************************************
*                    SEGGER Microcontroller GmbH                     *
*        Solutions for real time microcontroller applications        *
**********************************************************************
*                                                                    *
*        (c) 1996 - 2020  SEGGER Microcontroller GmbH                *
*                                                                    *
*        Internet: www.segger.com    Support:  support@segger.com    *
*                                                                    *
**********************************************************************

** emWin V6.10 - Graphical user interface for embedded applications **
emWin is protected by international copyright laws.   Knowledge of the
source code may not be used to write a similar product.  This file may
only  be used  in accordance  with  a license  and should  not be  re-
distributed in any way. We appreciate your understanding and fairness.
----------------------------------------------------------------------
File        : WM_TransparentWindows.c
Purpose     : Sample that shows how to create fully transparent and
              semi-transparent windows in emWin.
Requirements: WindowManager - (x)
              MemoryDevices - ( )
              AntiAliasing  - ( )
              VNC-Server    - ( )
              PNG-Library   - ( )
              TrueTypeFonts - ( )
---------------------------END-OF-HEADER------------------------------
*/

#include "DIALOG.h"

/*********************************************************************
*
*       Defines
*
**********************************************************************
*/
//
// Make sure to use colors that have transparency bits set
// When using BGR mode, the format of a color should look like this:
// 0xTTBBGGRR where T stands for transparency
//
#define COLOR_1    GUI_MAKE_COLOR(0x60EBC2FB)
#define COLOR_2    GUI_MAKE_COLOR(0xC0EEC1A6)
//
// Properties for gray background pattern.
// This pattern should emphasize the semi-transparent drawings.
//
#define BK_COLOR_1 GUI_MAKE_COLOR(0x00666666)
#define BK_COLOR_2 GUI_MAKE_COLOR(0x00999999)
#define RECT_SIZE  8

/*********************************************************************
*
*       Static code
*
**********************************************************************
*/

/*********************************************************************
*
*       _cbWin0
*/
static void _cbWin0(WM_MESSAGE * pMsg) {
  GUI_RECT Rect;

  switch (pMsg->MsgId) {
  case WM_PAINT:
    //
    // Draw something
    //
    WM_GetClientRect(&Rect);
    Rect.x0 += 5;
    Rect.y0 += 5;
    Rect.x1 -= 5;
    Rect.y1 -= 5;
    GUI_SetPenSize(5);
    GUI_SetColor(GUI_RED);
    GUI_AA_DrawRoundedRectEx(&Rect, 3);
    break;
  default:
    WM_DefaultProc(pMsg);
    break;
  }
}

/*********************************************************************
*
*       _cbWin1
*/
static void _cbWin1(WM_MESSAGE * pMsg) {
  GUI_RECT Rect;

  switch (pMsg->MsgId) {
  case WM_PAINT:
    //
    // Enable alpha blending to use semi-transparency
    //
    GUI_EnableAlpha(1);
    //
    // Draw something...
    // Make sure to use colors that have transparency bits set
    // When using BGR mode, the format of a color should look like this:
    // 0xTTBBGGRR where T stands for transparency
    //
    WM_GetClientRect(&Rect);
    GUI_DrawGradientRoundedH(Rect.x0, Rect.y0, Rect.x1, Rect.y1, 3, COLOR_1, COLOR_2);
    //
    // Disable alpha blending when semi-transparent drawing operations are done.
    // If it doesn't get disabled, it might have a heavy impact on performance.
    //
    GUI_EnableAlpha(0);
    break;
  default:
    WM_DefaultProc(pMsg);
    break;
  }
}

/*********************************************************************
*
*       _DrawBkPattern
*
*  Purpose: This routine draws the grey background pattern to highlight
*  the semi-transparent drawings made in this sample.
*/
static void _DrawBkPattern(void) {
  int       i, j;
  int       xSize, ySize;
  GUI_COLOR Color;
  U8        a;

  xSize = LCD_GetXSize();
  ySize = LCD_GetYSize();
  a     = 0;
  for (i = 0; i < xSize; i += RECT_SIZE) {
    a ^= 1;
    for(j = 0; j < ySize; j += RECT_SIZE) {
      a ^= 1;
      Color = (a % 2) ? BK_COLOR_1 : BK_COLOR_2;
      GUI_SetColor(Color);
      GUI_FillRect(i, j, i + RECT_SIZE, j + RECT_SIZE);
    }
  }
}

/*********************************************************************
*
*       Public code
*
**********************************************************************
*/
/*********************************************************************
*
*       MainTask
*/
void MainTask(void) {
  //
  // Init GUI
  //
  GUI_Init();
  _DrawBkPattern();
  //
  // Create two windows both having the WM_CF_HASTRANS flag
  // This flag makes a window or widget fully transparent
  //
  WM_CreateWindowAsChild(10, 10, 100, 100, WM_HBKWIN, WM_CF_SHOW | WM_CF_HASTRANS, _cbWin0, 0);
  WM_CreateWindowAsChild(120, 10, 100, 100, WM_HBKWIN, WM_CF_SHOW | WM_CF_HASTRANS, _cbWin1, 0);

  while (1) {
    GUI_Delay(100);
  }
}

/*************************** End of file ****************************/