showimg.cpp

这是一个自己开发的键盘驱动代码

/****************************************************************************
** $Id: qt/showimg.cpp   3.3.6   edited Aug 31 2005 $
**
** Copyright (C) 1992-2005 Trolltech AS.  All rights reserved.
**
** This file is part of an example program for Qt.  This example
** program may be used, distributed and modified without limitation.
**
*****************************************************************************/

#include "showimg.h"

#include <qlabel.h>
#include <qpainter.h>
#include <qapplication.h>
#include <qmessagebox.h>

ImageViewer::ImageViewer( QWidget *parent, const char *name, int wFlags )
    : QWidget( parent, name, wFlags ),
      conversion_flags( PreferDither )
{
		pwidget = (QSplitter*)parentWidget();
    alloc_context = 0;
    
    isFullScreen = false;
    screenToggled = false;
    newImage = true;

    status = new QLabel(this);
    status->setFrameStyle( QFrame::WinPanel | QFrame::Sunken );
    status->setFixedHeight( fontMetrics().height() + 4 );
    status->setBackgroundColor( white );

    setMouseTracking( TRUE );

}

ImageViewer::~ImageViewer()
{
    if ( alloc_context ) QColor::destroyAllocContext( alloc_context );
    if ( other == this ) other = 0;
}

/*
  This function loads an image from a file and resizes the widget to
  exactly fit the image size. If the file was not found or the image
  format was unknown it will resize the widget to fit the errorText
  message (see above) displayed in the current font.

  Returns TRUE if the image was successfully loaded.
*/
 bool ImageViewer::loadImage( const QString& fileName )
{
		newImage = 1;
		screenToggled = false;
    filename = fileName;
    bool ok = FALSE;
    if ( !filename.isEmpty() ) {
			QApplication::setOverrideCursor( waitCursor ); // this might take time
			ok = image.load(filename, 0);
			if ( ok ) {
				ok = reconvertImage();
			}
			if ( ok ) {
				scale();
				setCaption( filename );			// set window caption
			} else {
	    	pm.resize(0,0);				// couldn't load image
	    	update();
			}
			QApplication::restoreOverrideCursor();	// restore original cursor
    }
    return ok;
}

void ImageViewer::updateStatus()
{
		QString message, moremsg;
		if ( pm.size() != QSize( 0, 0 ) ) {
			message.sprintf("%dx%d", image.width(), image.height());
			if ( screenToggled && !isFullScreen ) {
				if ( pm.size() != pmScaledBackup.size() ) {
	    		moremsg.sprintf(" [%dx%d]", pmScaledBackup.width(),	pmScaledBackup.height());
	    		message += moremsg;
				} 
			} else if ( !isFullScreen && pm.size() != pmScaled.size() ) {
	    	moremsg.sprintf(" [%dx%d]", pmScaled.width(),	pmScaled.height());
	    	message += moremsg;
			} else if ( isFullScreen ) {
	    	moremsg.sprintf(" [%dx%d]", pmFullScreen.width(),	pmFullScreen.height());
	    	message += moremsg;
			}
			moremsg.sprintf(", %d bits ", image.depth());
			message += moremsg;
		}
		status->setText( message );
}
	
bool ImageViewer::reconvertImage()
{
    bool success = FALSE;

    if ( image.isNull() ) return FALSE;

    if ( alloc_context ) {
	QColor::destroyAllocContext( alloc_context );
	alloc_context = 0;
    }

    QApplication::setOverrideCursor( waitCursor ); // this might take time
    if ( pm.convertFromImage(image, conversion_flags) ) {
    	success = TRUE;				// load successful
    } else {
    	pm.resize(0,0);
    }				// couldn't load image
    QApplication::restoreOverrideCursor();	// restore original cursor

    return success;				// TRUE if loaded OK
}

/*
  This functions scales the pixmap in the member variable "pm" to fit the
  widget size and  puts the resulting pixmap in the member variable "pmScaled".
*/

void ImageViewer::scale()
{
		int h = height() - status->height();
		
    if ( image.isNull() ) return;

    QApplication::setOverrideCursor( waitCursor ); // this might take time
    if ( width() >= pm.width() && h >= pm.height() )
    {						// no need to scale if widget
			pmScaled = pm;				// size equals pixmap size
			if ( isFullScreen ) pmFullScreen = pmScaled;
	  	else pmScaledBackup = pmScaled;
    } else {
	    QWMatrix m;				// transformation matrix
	    
	    if ( pm.width() == pm.height() ) {
	    	if ( width() >= h ) {
	    		m.scale( ( (double)h ) / pm.width(),// define scale factors
		    		( (double)h ) / pm.width() );
		    } else {
		    	m.scale( ( (double)width() ) / pm.width(),// define scale factors
		    		( (double)width() ) / pm.width() );
		    }
		  }
		  
		  if ( pm.width() > pm.height() ) {
		  		if ( ( (double)pm.width() / width() ) >= ( (double)pm.height() / h ) ) {
		  			m.scale( ( (double)width() ) / pm.width(),// define scale factors
		    			( (double)width() ) / pm.width() );
		    	} else {
		    		m.scale( ( (double)h ) / pm.height(),// define scale factors
		    			( (double)h ) / pm.height() );
	    		}
	    }
	    
	    if ( pm.width() < pm.height() ) {
		  		if ( ( (double)pm.width() / width() ) >= ( (double)pm.height() / h ) ) {
		  			m.scale( ( (double)width() ) / pm.width(),// define scale factors
		    			( (double)width() ) / pm.width() );
		    	} else {
		    		m.scale( ( (double)h ) / pm.height(),// define scale factors
		    			( (double)h ) / pm.height() );
	    		}
	    }
	  	pmScaled = pm.xForm( m );		// create scaled pixmap
	  	if ( isFullScreen ) pmFullScreen = pmScaled;
	  	else pmScaledBackup = pmScaled;
    }
    screenToggled = false;
    updateStatus();
    QApplication::restoreOverrideCursor();	// restore original cursor
}

/*
  The resize event handler, if a valid pixmap was loaded it will call
  scale() to fit the pixmap to the new widget size.
*/

void ImageViewer::resizeEvent( QResizeEvent * )
{
		int h = height() - status->height();
    status->setGeometry(0, h, width(), status->height());
			
    if ( pm.size() == QSize( 0, 0 ) )		// we couldn't load the image
			return;
			
    if ( !screenToggled || newImage ) scale();// scale pmScaled to window
    newImage = false;
}

/*
  Draws the portion of the scaled pixmap that needs to be updated or prints
  an error message if no legal pixmap has been loaded.
*/
void ImageViewer::paintEvent( QPaintEvent *e )
{
		int h = height() - status->height();
		
    if ( pm.size() != QSize( 0, 0 ) ) {		// is an image loaded?
			QPainter painter(this);
			painter.setClipRect(e->rect());
			if ( isFullScreen ) {
				updateStatus();
				painter.drawPixmap( ( width() - pmFullScreen.width() ) / 2, ( h - pmFullScreen.height() ) / 2, pmFullScreen );
			} else if ( !isFullScreen && screenToggled ) {
				updateStatus();
				painter.drawPixmap( ( width() - pmScaledBackup.width() ) / 2, ( h - pmScaledBackup.height() ) / 2, pmScaledBackup );
			} else {
				updateStatus();
				painter.drawPixmap( ( width() - pmScaled.width() ) / 2, ( h - pmScaled.height() ) / 2, pmScaled );
    	}
    }
}

ImageViewer* ImageViewer::other = 0;

void ImageViewer::mouseReleaseEvent( QMouseEvent * )
{
    emit clicked();
}
	
void ImageViewer::fullScreen()
{
		isFullScreen = true;
		oriPoint = pos();
		reparent( 0, QPoint( 0, 0 ) );
		showFullScreen();
}

void ImageViewer::toggleFullScreen()
{
		screenToggled = true;
    if ( isFullScreen ) normalView();
    else fullScreen();
}

void ImageViewer::normalView()
{
		isFullScreen = false;
		showNormal();
		reparent( pwidget, oriPoint );
		show();
}