How to change background color of an image when image is a transparent image.

Kusum Swarankar · Jun 14th 2018, 8:03am

Hi,
is there any way to change the background color of a transparent image.

mrohit2011 · Jun 14th 2018, 3:25pm

use the following,

WM_PAINT:
GUI_SetBkColor(GUI_WHITE);
GUI_Clear();
GUI_PNG_Draw(_acwifi_connected,sizeof(_acwifi_connected) , 0,0);
break;

Regards,
Rohit M.

Kusum Swarankar · Jun 15th 2018, 7:59am

I am doing the same and initially its fine. but the moment another window comes on top background color is changing to black. what can be the reason?

SEGGER - Schoenen · Jun 15th 2018, 9:25am

Hi,

Please give the example attached a try. A PNG gets drawn with white as back ground color and a window on top. The window gets hidden and shown again each second.

Regards,
Sven

Kusum Swarankar · Jun 18th 2018, 7:47am

ok let me explain you again.
I have a window on that i want to create a button on that button i want to set image for pressed and unpressed both. image which i am using is transparent. I want the same image to be used and just change the background color in callback function of that button like this.

static void _cbButton(WM_MESSAGE * pMsg)
{
switch (pMsg->MsgId) {
case WM_PAINT:
if(BUTTON_IsPressed(pMsg->hWin))
{
GUI_SetBkColor(GUI_RED);
GUI_Clear();
GUI_DrawBitmap(&buttonicon1,0,0);
}
else
{
GUI_SetBkColor(GUI_GREEN);
GUI_Clear();
GUI_DrawBitmap(&buttonicon1,0,0);
}
break;
default:
BUTTON_Callback(pMsg);
break;
}
}

THIS FUNCTION will set the background properly. now at some point of time popup comes on top of that window where button was drawn. when that popup goes (deleted) background color of that button also went off and now it is black. i am not able to set the background color again.. hope you understood.

SEGGER - Schoenen · Jun 22nd 2018, 11:00am

Hi,

I have no issue drawing a bitmap on button. No matter if a window gets on top of or not.

Try the example attached.

Regards,
Sven

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