Easy to Use Class for ScreenCapture to Printer

• Download demo project - 27.9 KB
• Download source files - 5.6 KB

Introduction

For a project I'm working on, I needed a way to easily create screen shots of the foreground dialog and to print the image directly to the default printer. As I couldn't find the right solution ready for use, I wrote a quick 'n dirty own class, based on the many articles found at The Code Project.

The attached code builds a very easy to use screen capture function, which can be called in a button callback for example. It is possible to adjust the capture area and the print orientation. The desired area will be captured and printed.

Using the Code

As said, one of the aims was to make the class as easy to use as possible.

1. Add the files PrntScreen.cpp and PrntScreen.h to your project.
2. In your application (or dialog class, etc.), add the following line:
   C++

   #include "PrntScreen.h"

3. At the place, where you want to capture and print the screen, add the following lines to your code:

   Example 1:

   C++

   CPrntScreen * ScrCap;
   ScrCap = new CPrntScreen();  //create instance
   ScrCap->DoPrntScreen();  //execute capture function
   delete ScrCap;  //remove instance
   ScrCap=NULL;

   Example 2:

   C++

   CPrntScreen * ScrCap;
   ScrCap = new CPrntScreen("Some error occurred!!!","Message");
   ScrCap->DoPrntScreen(1,1,true);
   delete ScrCap;
   ScrCap=NULL;

Example 1 uses just the default parameters, whereas Example 2 uses available options.

Description

Constructor

The constructor of the class is defined as CPrntScreen(char* sErrTxt, char* sCaption), thus accepting two parameters. The idea was to permit customizing the error message box for your own needs/language.

Description of the parameters:

• char* sErrTxt = pointer to characters pointing to a desired error message
• char* sCaption = pointer to characters pointing to a desired message box caption
  if the parameters are omitted, the default text/caption will be shown in case of an error.

Functions

The class contains just one function, DoPrntScreen(int nArea, int nOrientation, bool bDialog).
Description of the parameters:

• nArea determines the area of screen to be captured, with:
  • 0 = Whole screen
  • 1 = Foreground window
  • 2 = Foreground window - Client area
    If parameter is omitted, 0 (Whole Screen) will be used by default
• nOrientation determines the print orientation, with:
  • 1 = Portrait (you may also use DMORIENT_PORTRAIT)
  • 2 = Landscape (you may also use DMORIENT_LANDSCAPE)
    This parameter is only used, if bDialog=false
    If parameter is omitted, 2 (Portrait) will be used by default
• bDialog controls, if a printer dialog will be shown:
  • false = Use default printer without showing dialog
  • true = Show printer dialog
    If parameter is omitted, false (Default Printer) will be used by default

History

• Version 1.0: First version
• Version 1.1: Updated version
  Following changes where done:
  • Defined default parameters for even easier use (see example 1 above)
  • Introduced a flag for enabling the use of the printer dialog
  • Changed the stretching function. Now the captured area will be stretched to printer page in the relation, it has to the whole screen. Capturing of smaller dialogs will not anymore cause huge printouts. :) Having done this, it is definitely best to set print orientation to landscape!
  • The above changes are compatible to the old version, thus no code change is needed when using the new version. Just drop in the new code. Only the printout may change proportions, due to the change of stretching. :(
• Version 1.1A: Bug fix, fixing an error which caused empty pages on some printers
• Version 1.2: Bug fix (hopefully) and new features. This new version includes:
  • The code suggested by Dieter Hammer, which should eliminate that nasty blank page problem
  • Correct printing of dialogs, which were partially pushed out of desktop area
  • Proportional correct printout, independent of paper orientation
  • Checking, if printer is actually capable of printing images
  • And I have added a demo project. The prj file is for VC7, sorry, I don't have VC6 anymore. Just look to the last callback handlers in "PrintDlg.cpp"