How does GDI+ decide which to use, alphablending or dithering? - C / C++ / MFC Discussion Boards

shanmugarajaa16-Jan-13 18:37

16-Jan-13 18:37

Dear Friends,
I am working for MFC application. But I dont know about MFC architecture, classes, why CWinApp, CDocument, Cview and where execution starts and execution flow etc... Iam keen to learn all those things. So kindly anyone help me.

Thanks and Regards,

S.Shanmuga Raja

Re: MFC architecture

SujayG16-Jan-13 18:49

SujayG

16-Jan-13 18:49

Hi There ,

MFC architecture is too big to be discussed on a forum .

I would suggest you go through the book of Jeff Prosise, to understand it better .

Sujay Ghosh

Blog : http://sujay-ghosh.blogspot.com

Re: MFC architecture

«_Superman_»16-Jan-13 21:56

«_Superman_»

16-Jan-13 21:56

What you're actually asking for is the Document-View architecture supported by MFC.
You can start here - Document/View Architecture[^]

«_Superman_»
I love work. It gives me something to do between weekends.

Microsoft MVP (Visual C++) (October 2009 - September 2013)

Polymorphism in C

Re: MFC architecture

Alan Balkany17-Jan-13 5:14

Alan Balkany

17-Jan-13 5:14

This is a good introduction to MFC: http://msdn.microsoft.com/en-us/library/aa716527%28v=vs.60%29.aspx[^]

Re: MFC architecture

Maximilien17-Jan-13 9:29

Maximilien

17-Jan-13 9:29

For an insider understanding of MFC, you can have a look at the MFC Internals[^] books.

Nihil obstat

Re: MFC architecture

SujayG17-Jan-13 18:54

SujayG

17-Jan-13 18:54

MFC Internals would be too much for him. Right now , he is trying to understand the MFC architecture . Wink | ;)

Blog : http://sujay-ghosh.blogspot.com

Re: MFC architecture

Maximilien18-Jan-13 1:26

Maximilien

18-Jan-13 1:26

If I remember correctly, that book, while being more "advanced", was a good reading and help understanding the mess that was MFC; it is a little better now.

Nihil obstat

How does GDI+ decide which to use, alphablending or dithering?

Code-o-mat16-Jan-13 10:49

Code-o-mat

16-Jan-13 10:49

Hey guys!

Does any of you have an idea how GDI+ -when filling a rectangle or a region with a color that has an alpha component set- decides to use dithering instead of "real" blending? We are using a third-party library to generate PDF files. When using a printer DC as a "reference" to generate the PDF document, GDI+ seems to use "normal" color blending when filling an area with a translucent color, but when using a screen DC to do the same it "magically" decides to use dithering which produces a "less satisfying" result.

> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> If it doesn't matter, it's antimatter.<

Re: How does GDI+ decide which to use, alphablending or dithering?

JackDingler16-Jan-13 11:13

JackDingler

16-Jan-13 11:13

In many cases, the device driver determines how the GDI+ functions operate.
The printer driver for your printer may not support alpha blending.

You might try using a memory DC to build up your graphics, then blitting that to your printer DC.

Re: How does GDI+ decide which to use, alphablending or dithering?

Code-o-mat16-Jan-13 23:21

Code-o-mat

16-Jan-13 23:21

It's the other way around actually (read my original post again), when using the printer, i get alpha, when using a screen based DC, i get dithering, this is why i don't understand it, since i KNOW that i can use e.g. AlphaBlend[^] on the screen without any problems, or if i use GetDeviceCaps[^] on the screen DC i see that it supports blending.
I kinda know that the capabilities of the device is -at least usually- determined by the driver "under" it, what i would like to know is what GDI+ does to come to the conclusion that the screen-based device is incapable of blending and thus resorts to "low quality" dithering.

> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> If it doesn't matter, it's antimatter.<

Re: How does GDI+ decide which to use, alphablending or dithering?

JackDingler17-Jan-13 5:07

JackDingler

17-Jan-13 5:07

If you're getting dithering, then your bits per pixel may be set to less than 24 bits.

Like I said, the device drivers do most of that work. GDI+ doesn't really make any decisions.

I've never seen reliable results in alpha blending from GDI+. I avoid it and either write my own code to do it, or use OpenGL.

how to get window color?

VCProgrammer16-Jan-13 1:36

VCProgrammer

16-Jan-13 1:36

hi all,

i want to get window color that is appear on window border,start menu and taskbar.

how can i do this?

thanks in advance.

Re: how to get window color?

Richard MacCutchan16-Jan-13 2:12

Richard MacCutchan

16-Jan-13 2:12

See the GetSysColor function[^].

One of these days I'm going to think of a really clever signature.

Re: how to get window color?

VCProgrammer16-Jan-13 17:40

VCProgrammer

16-Jan-13 17:40

yes i already use this .

i am using windows 7, and set Leaf color here "Control Panel\Appearance and Personalization\Personalization\Window Color and Appearance"

but using GetSysColor this color cant get even i chk this for all values.

please help me which value is use to get this color?

thanks.

Re: how to get window color?

Jochen Arndt16-Jan-13 22:19

Jochen Arndt

16-Jan-13 22:19

With enabled themes you can use GetThemeColor[^]. See also the CP article Add XP Visual Style Support to OWNERDRAW Controls[^]. It may contain useful information (the demo application is based on the no longer available ThemeExplorer from Microsoft which shows the colors for the various GUI elements).

Re: how to get window color?

VCProgrammer18-Jan-13 18:42

VCProgrammer

18-Jan-13 18:42

//i am use GetThemeColor like this.

// Getting the text color used for taskbar captions.
	HTHEME hTheme = ::OpenThemeData(NULL, VSCLASS_TASKBAND);
	ATLASSERT(hTheme);

	COLORREF clrText = 0;
	if(hTheme)
	{
		const HRESULT hr = ::GetThemeColor(hTheme, TDP_GROUPCOUNT, 0, 
										   TMT_BORDERCOLOR, &clrText);		


		ATLASSERT(SUCCEEDED(hr));

		::CloseThemeData(hTheme);
	}

	// Classic visual scheme.
	::FillRect(pDC->m_hDC, &banner_rect, ::GetSysColorBrush(CTLCOLOR_DLG));

	// Themed visual scheme. Draw transparently.
	::DrawThemeParentBackground(obj_RecProfDlg->GetSafeHwnd(), pDC->m_hDC, &banner_rect);

but its not useful

so please help me ,what values i can use GetThemeColor

thanks.

How to draw a banner and button ?

VCProgrammer15-Jan-13 20:24

VCProgrammer

15-Jan-13 20:24

hi all,

i want t draw banner and button for the dialog box according to current system theme.

please help me how can i do this.

thanks in advance.

Re: How to draw a banner and button ?

_Flaviu15-Jan-13 20:49

_Flaviu

15-Jan-13 20:49

For button, you can use CBitmapButton[^], and for the banner, you can use CStatic[^], where you can put there a bitmap, like banner ... of course, you can find here a derived CButton controls ...

Re: How to draw a banner and button ?

VCProgrammer15-Jan-13 21:08

VCProgrammer

15-Jan-13 21:08

i dont want to use image for this.

i want to get current system theme and its color than according to this draw the graphics.

what can i do for this?

thanks.

Re: How to draw a banner and button ?

_Flaviu15-Jan-13 21:26

_Flaviu

15-Jan-13 21:26

Well, then you only must setup a style for your application (setup manifest file) and you'll have a current system style on your button and CStatic. If I well understand ...

Re: How to draw a banner and button ?

VCProgrammer15-Jan-13 21:34

VCProgrammer

15-Jan-13 21:34

yes

how can use setup style?

Re: How to draw a banner and button ?

_Flaviu15-Jan-13 22:14

_Flaviu

15-Jan-13 22:14

Very simple: add manifest file in your project resource folder, and then open Resource.h:

C++

#if _MSC_VER <= 1200
#ifndef IDR_MANIFEST
#define IDR_MANIFEST                    1
#endif
#ifndef	RT_MANIFEST
#define RT_MANIFEST                     24
#endif
#endif // _MSC_VER <= 1200

if you don't have a manifest file, I could send you through email ...

Check here[^] too.

modified 16-Jan-13 4:24am.

Re: How to draw a banner and button ?

Richard MacCutchan15-Jan-13 22:46

Richard MacCutchan

15-Jan-13 22:46

Take a look at this section on MSDN[^].

One of these days I'm going to think of a really clever signature.

it's my first useful code.. and there's error that i can't understan :(

eng.immortal15-Jan-13 18:20

eng.immortal

15-Jan-13 18:20

i have written a code in C++ for employees using OOP .. and after building it ,this error message appear : "

1>MSVCRTD.lib(crtexew.obj) : error LNK2019: unresolved external symbol _WinMain@16 referenced in function ___tmainCRTStartup

"

can anybody tell me what does that mean ? & and what should i do to run the program ?

Re: it's my first useful code.. and there's error that i can't understan :(

_Flaviu15-Jan-13 19:37

_Flaviu

15-Jan-13 19:37

See here[^], a solution of your problem.

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.