LISTWHEEL with semitransparent background

mastupristi · February 8, 2018 at 11:05 PM

How can I get the selected item of a LISTWHEEL item to have a semi-transparent background color?

I tried this:

C

#include "GUI.h"
#include "LISTWHEEL.h"
#include <stdio.h>


const char *pList[] =
{
	"1st",
	"2nd",
	"3rd",
	"4th",
	NULL,
};


void MainTask(void)
{
  GUI_Init();


//  GUI_EnableAlpha(1);
  GUI_SetBkColor(GUI_WHITE);
  GUI_Clear();


  GUI_DrawGradientV(13, 5, 70, 65, GUI_YELLOW, GUI_GREEN);
  LISTWHEEL_Handle hWin;


  hWin = LISTWHEEL_CreateEx(10, 10, 50, 45, WM_HBKWIN, WM_CF_SHOW | WM_CF_HASTRANS, 0, GUI_ID_LISTWHEEL0, pList);
  LISTWHEEL_SetBkColor(hWin, LISTWHEEL_CI_SEL, GUI_MAKE_COLOR((0x70uL << 24) | 0x0000FF));
  LISTWHEEL_SetBkColor(hWin, LISTWHEEL_CI_UNSEL, GUI_TRANSPARENT);


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

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and the result is:

[Blocked Image: https://s17.postimg.org/73dzfhw8f/semitransparent_List_Wheel.png]

instead, I can get the text semi-transparent if I try to get it.

best regards
Max

SEGGER - Schoenen · February 14, 2018 at 3:27 PM

Hi,

Unfortunately, it is not that easy.

If the LISTWHEEL gets created with the transparency flag set it will be completely transparent and does not fill its background.

If you want a semi transparent background you have to set a owner draw function. Within that owner draw function you check for the item which background should be drawn. Then call GUI_EnableAlpha(1) to enable the use of the alpha bits of a color, perform a clear, and disable the use of the alpha bits again. After that call LISTWHEEL_OwnerDraw() to draw the rest of the widget.

Here is an example on you this can be achieved.

C

#include "DIALOG.h"


/*********************************************************************
*
*   	Externals
*
**********************************************************************
*/


/*********************************************************************
*
*   	Defines
*
**********************************************************************
*/
#define ID_WINDOW_0   	(GUI_ID_USER + 0x00)
#define ID_LISTWHEEL_0	(GUI_ID_USER + 0x01)


/*********************************************************************
*
*   	Static data
*
**********************************************************************
*/
/*********************************************************************
*
*   	_aDialogCreate
*/
static const GUI_WIDGET_CREATE_INFO _aDialogCreate[] = {
  { WINDOW_CreateIndirect,	"Window",	ID_WINDOW_0,  	0,  0, 480, 272, 0, 0x0, 0 },
  { LISTWHEEL_CreateIndirect, "Listwheel", ID_LISTWHEEL_0, 200, 20,  80, 120, 0, 0x0, 0 },
};


/*********************************************************************
*
*   	Static code
*
**********************************************************************
*/
/*********************************************************************
*
*   	_OwnerDraw
*/
static int _OwnerDraw(const WIDGET_ITEM_DRAW_INFO * pDrawItemInfo) {
  switch (pDrawItemInfo->Cmd) {
  case WIDGET_ITEM_DRAW:
	//
	// Check if the current item is the selected
	//
	if (pDrawItemInfo->ItemIndex == LISTWHEEL_GetSel(pDrawItemInfo->hWin)) {
  	//
  	// Enable alpha, the upper 8 bits (most significant) will be taken into account
  	//
  	GUI_EnableAlpha(1);
  	//
  	// Get LISTWHEEL color and set it as current bk color
  	//
  	GUI_SetBkColor(LISTWHEEL_GetBkColor(pDrawItemInfo->hWin, LISTWHEEL_CI_SEL));
  	//
  	// Clear item area with the color
  	//
  	GUI_ClearRect(pDrawItemInfo->x0, pDrawItemInfo->y0, pDrawItemInfo->x1, pDrawItemInfo->y1);
  	//
  	// Disable alpha again.
  	//
  	GUI_EnableAlpha(0);
	}
	return LISTWHEEL_OwnerDraw(pDrawItemInfo);
  case WIDGET_ITEM_DRAW_BACKGROUND:
	return LISTWHEEL_OwnerDraw(pDrawItemInfo);
  default:
	return LISTWHEEL_OwnerDraw(pDrawItemInfo);
  }
}


/*********************************************************************
*
*   	_cbDialog
*/
static void _cbDialog(WM_MESSAGE * pMsg) {
  WM_HWIN  hItem;
  int  	NCode;
  int  	Id;
  GUI_RECT Rect;


  switch (pMsg->MsgId) {
  case WM_INIT_DIALOG:
	//
	// Initialization of 'Listwheel'
	//
	hItem = WM_GetDialogItem(pMsg->hWin, ID_LISTWHEEL_0);
	LISTWHEEL_AddString(hItem, "String0");
	LISTWHEEL_AddString(hItem, "String1");
	LISTWHEEL_AddString(hItem, "String2");
	LISTWHEEL_AddString(hItem, "String3");
	LISTWHEEL_AddString(hItem, "String4");
	LISTWHEEL_AddString(hItem, "String5");
	LISTWHEEL_AddString(hItem, "String6");
	LISTWHEEL_AddString(hItem, "String7");
	LISTWHEEL_AddString(hItem, "String8");
	LISTWHEEL_AddString(hItem, "String9");
	LISTWHEEL_AddString(hItem, "String10");


	WM_SetHasTrans(hItem);                  	// Same as if created with WM_CF_HASTRANS
	LISTWHEEL_SetOwnerDraw(hItem, _OwnerDraw);  // Set a owner draw
	LISTWHEEL_SetBkColor(hItem, LISTWHEEL_CI_SEL, GUI_MAKE_COLOR((0x70uL << 24) | 0x0000FF));
	LISTWHEEL_SetBkColor(hItem, LISTWHEEL_CI_UNSEL, GUI_TRANSPARENT);


	break;
  case WM_NOTIFY_PARENT:
	Id	= WM_GetId(pMsg->hWinSrc);
	NCode = pMsg->Data.v;
	switch(Id) {
	case ID_LISTWHEEL_0: // Notifications sent by 'Listwheel'
  	switch(NCode) {
  	case WM_NOTIFICATION_CLICKED:
    	break;
  	case WM_NOTIFICATION_RELEASED:
    	break;
  	case WM_NOTIFICATION_SEL_CHANGED:
    	break;
  	}
  	break;
	}
	break;
  case WM_PAINT:
	WM_GetClientRect(&Rect);
	GUI_DrawGradientH(Rect.x0, Rect.y0, Rect.x1, Rect.y1, GUI_WHITE, GUI_BLACK);
	GUI_DrawLine(Rect.x0, Rect.y0, Rect.x1, Rect.y1);
	GUI_DrawLine(Rect.x0, Rect.y1, Rect.x1, Rect.y0);
	break;
  default:
	WM_DefaultProc(pMsg);
	break;
  }
}


/*********************************************************************
*
*   	Public code
*
**********************************************************************
*/
/*********************************************************************
*
*   	MainTask
*/
void MainTask(void) {
  GUI_Init();
  WM_MULTIBUF_Enable(1);
  GUI_CreateDialogBox(_aDialogCreate, GUI_COUNTOF(_aDialogCreate), _cbDialog, WM_HBKWIN, 0, 0);
  while (1) {
	GUI_Delay(100);
  }
}


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

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Regards
Sven

LISTWHEEL with semitransparent background

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