Understanding GDI mapping modes and other functions

This tool was contributed by Hans Wedemeyer.

MapMode.exe is an interactive tool that can help a programmer better understand various graphics functions and their interactions.

It demonstrates the interactions of

SetMapMode()    // all eight modes
SetWindowExt ()
SetViewportExt ()
SetViewportOrg ()
CreateCompatibleBitmap()
BitBlt( )

Have you ever wondered what a printed page will look like in a particular map mode, here's thre answer and you don't have to write code to find out !

Ever wondered what all those arguments to BitBlt() do ! now you can find out!

Open eight windows and compare all eight map modes at the same time !

When you run the program, there appears a "control panel", on it are various buttons to adjust the parameters for each function. as you adjust the screen is repainted and the change takes place immediately.

Consider these to be in the program's OnDraw()

void MapMode::OnDraw(CDC* pDC )
{
    CRect rect;
    GetClientRect(&rect);

    if ( pDC->IsPrinting())
    {
        rect.left = 0;
        rect.top = 0;
        rect.right = pDC->GetDeviceCaps(HORZRES);
        rect.bottom = pDC->GetDeviceCaps(VERTRES);
    }

    pDC->SetMapMode ( m_nMapMode );

    pDC->SetWindowExt ( X, Y )

    pDC->SetViewportExt ( X , Y );

    pDC->SetViewportOrg ( X, Y );

    bmp.CreateCompatibleBitmap( pDC, X, Y );

   pDC->BitBlt( X1, Y1, X2, Y2, pBmpDC, X3, Y3, SRCCOPY );
}

You may draw a line to better understand or locate various x,y coordinates.

Additions made since the original tool.

Annotated origins for easy indentifaction.

Another new feature is "Find Origin" which help pin point in which direction the origin could be, useful if you loose the origin off screen.

Download file



Comments

  • There are no comments yet. Be the first to comment!

Leave a Comment
  • Your email address will not be published. All fields are required.

Top White Papers and Webcasts

  • Live Event Date: August 20, 2014 @ 1:00 p.m. ET / 10:00 a.m. PT When you look at natural user interfaces as a developer, it isn't just fun and games. There are some very serious, real-world usage models of how things can help make the world a better place – things like Intel® RealSense™ technology. Check out this upcoming eSeminar and join the panel of experts, both from inside and outside of Intel, as they discuss how natural user interfaces will likely be getting adopted in a wide variety …

  • Savvy enterprises are discovering that the cloud holds the power to transform IT processes and support business objectives. IT departments can use the cloud to redefine the continuum of development and operations—a process that is becoming known as DevOps. Download the Executive Brief DevOps: Why IT Operations Managers Should Care About the Cloud—prepared by Frost & Sullivan and sponsored by IBM—to learn how IBM SmartCloud Application services provide a robust platform that streamlines …

Most Popular Programming Stories

More for Developers

Latest Developer Headlines

RSS Feeds