WM Late Clipping (Sample)

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WM_LateClipping.c
Late clipping requires much fewer redrawing operations.
File(s) required
  • WM_LateClipping.c
Runs in simulation Yes
Runs on target Yes
Download WM_LateClipping.c

This sample shows the difference between late and early clipping.

Late clipping vs. early clipping

Early clipping is the default clipping mode. In this mode clipping is performed before windows receive paint events. In case the current window needs to be clipped, it will receive more than one WM_PAINT message within a single drawing process.

In the late clipping mode, windows always receive only one single WM_PAINT message. In this mode clipping is performed within the drawing operations.

Demo

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_LateClipping.c
Purpose     : Sample that shows the difference between late and early
              clipping in emWin.
Requirements: WindowManager - (x)
              MemoryDevices - ( )
              AntiAliasing  - ( )
              VNC-Server    - ( )
              PNG-Library   - ( )
              TrueTypeFonts - ( )
----------------------------------------------------------------------
*/

#include "GUI.h"
#include "WM.h"
#include "FRAMEWIN.h"
#include "BUTTON.h"

/*********************************************************************
*
*       Static data
*
**********************************************************************
*/
static WM_HWIN _hWin1;
static WM_HWIN _hWin2;
static WM_HWIN _hBut1;
static WM_HWIN _hBut2;
static int     _PaintCount1;
static int     _PaintCount2;

static GUI_COLOR _aColors[] = {
#if (GUI_USE_ARGB == 1)
  0xFFFF0000, 0xFF00FF00, 0xFF0000FF, 0xFFFFFF00, 0xFFA000A0, 0xFF00FFFF
#else
  0x0000FF, 0x00FF00, 0xFF0000, 0x00FFFF, 0xA000A0, 0xFFFF00
#endif
};

/*********************************************************************
*
*       Static code
*
**********************************************************************
*/
/*********************************************************************
*
*       _cbBkWin
*/
static void _cbBkWin(WM_MESSAGE* pMsg) {
  switch(pMsg->MsgId) {
  case WM_PAINT:
    GUI_SetBkColor(GUI_BLACK);
    GUI_Clear();
    GUI_SetColor(GUI_MAKE_COLOR(0x0060FF));
    GUI_DispStringAt("PaintCount (Early):", 0, 0);
    GUI_DispDecAt(_PaintCount1, 120, 0, 5);
    GUI_SetColor(GUI_MAKE_COLOR(0x00FFC0));
    GUI_DispStringAt("PaintCount (Late):", 0, 12);
    GUI_DispDecAt(_PaintCount2, 120, 12, 5);
    break;
  case WM_NOTIFY_PARENT:
    if (pMsg->Data.v == WM_NOTIFICATION_RELEASED) {
      if (pMsg->hWinSrc == _hBut1) {
        WM_InvalidateWindow(_hWin1);
        WM_InvalidateWindow(_hWin2);
      } else if (pMsg->hWinSrc == _hBut2) {
        _PaintCount1 = 0;
        _PaintCount2 = 0;
        WM_InvalidateWindow(pMsg->hWin);
      }
    }
    break;
  default:
    WM_DefaultProc(pMsg);
  }
}

/*********************************************************************
*
*       _cbTop
*/
static void _cbTop(WM_MESSAGE* pMsg) {
  switch(pMsg->MsgId) {
  case WM_PAINT:
    GUI_SetBkColor(GUI_MAGENTA);
    GUI_Clear();
    break;
  default:
    WM_DefaultProc(pMsg);
  }
}

/*********************************************************************
*
*       _cbFrameWin1
*/
static void _cbFrameWin1(WM_MESSAGE* pMsg) {
  switch(pMsg->MsgId) {
  case WM_PAINT:
    //
    // Draw something
    //
    GUI_SetBkColor(_aColors[_PaintCount1 % 6]);
    GUI_Clear();
    GUI_SetColor(GUI_MAKE_COLOR(0x0060FF));
    GUI_FillCircle(25, 25, 15);
    GUI_SetColor(GUI_BLACK);
    GUI_DrawCircle(25, 25, 15);
    //
    // Count paint event
    //
    _PaintCount1++;
    WM_InvalidateWindow(WM_HBKWIN);
    break;
  default:
    WM_DefaultProc(pMsg);
  }
}

/*********************************************************************
*
*       _cbFrameWin2
*/
static void _cbFrameWin2(WM_MESSAGE* pMsg) {
  switch(pMsg->MsgId) {
  case WM_PAINT:
    //
    // Draw something
    //
    GUI_SetBkColor(_aColors[_PaintCount2 % 6]);
    GUI_Clear();
    GUI_SetColor(GUI_MAKE_COLOR(0x00FFC0));
    GUI_FillCircle(25, 25, 15);
    GUI_SetColor(GUI_BLACK);
    GUI_DrawCircle(25, 25, 15);
    //
    // Count paint event
    //
    _PaintCount2++;
    WM_InvalidateWindow(WM_HBKWIN);
    break;
  default:
    WM_DefaultProc(pMsg);
  }
}

/*********************************************************************
*
*       _ShowDemo
*/
static void _ShowDemo(void) {
  WM_HWIN hWin0;
  WM_HWIN hWin1;
  WM_HWIN hWin2;
  WM_HWIN hFrame1;
  WM_HWIN hFrame2;
  WM_HWIN hClient1;
  WM_HWIN hClient2;

  WM_SetCallback(WM_HBKWIN, _cbBkWin);
  hFrame1  = FRAMEWIN_CreateEx( 10, 30, 140, 140, 0, WM_CF_SHOW, FRAMEWIN_CF_MOVEABLE, 0, "Early Clipping", _cbFrameWin1);
  hFrame2  = FRAMEWIN_CreateEx(170, 30, 140, 140, 0, WM_CF_SHOW, FRAMEWIN_CF_MOVEABLE, 0, "Late Clipping", _cbFrameWin2);
  hClient1 = WM_GetClientWindow(hFrame1);
  hClient2 = WM_GetClientWindow(hFrame2);
  //
  // To create a late clipping window, the flag WM_CF_LATE_CLIP has to be added
  //
  _hWin1   = WM_CreateWindowAsChild(0, 0, WM_GetWindowSizeX(hClient1), WM_GetWindowSizeY(hClient1), hClient1, WM_CF_SHOW, _cbFrameWin1, 0);
  _hWin2   = WM_CreateWindowAsChild(0, 0, WM_GetWindowSizeX(hClient2), WM_GetWindowSizeY(hClient2), hClient2, WM_CF_SHOW | WM_CF_LATE_CLIP, _cbFrameWin2, 0);
  _hBut1   = BUTTON_CreateEx( 10, 210, 140, 20, 0, WM_CF_SHOW, 0, 1);
  _hBut2   = BUTTON_CreateEx(170, 210, 140, 20, 0, WM_CF_SHOW, 0, 2);
  hWin0    = FRAMEWIN_CreateEx( 60,  80, 40, 40, 0, WM_CF_SHOW | WM_CF_STAYONTOP, FRAMEWIN_CF_MOVEABLE, 0, "Top 0", _cbTop);
  hWin1    = FRAMEWIN_CreateEx(220,  80, 40, 40, 0, WM_CF_SHOW | WM_CF_STAYONTOP, FRAMEWIN_CF_MOVEABLE, 0, "Top 1", _cbTop);
  hWin2    = FRAMEWIN_CreateEx(140, 170, 40, 40, 0, WM_CF_SHOW | WM_CF_STAYONTOP, FRAMEWIN_CF_MOVEABLE, 0, "Top 2", _cbTop);
  FRAMEWIN_SetResizeable(hWin0, 1);
  FRAMEWIN_SetResizeable(hWin1, 1);
  FRAMEWIN_SetResizeable(hWin2, 1);
  BUTTON_SetText(_hBut1, "Invalidate");
  BUTTON_SetText(_hBut2, "Reset counters");
  while(1) {
    GUI_Delay(50);
  }
}

/*********************************************************************
*
*       Public code
*
**********************************************************************
*/
/*********************************************************************
*
*       MainTask
*/
void MainTask(void) {
  //
  // Init GUI
  //
  GUI_Init();

  while(1) {
    _ShowDemo();
  }
}

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