GeneratePreviewThread Class Reference

#include <addPhotosDialog.h>

Inheritance diagram for GeneratePreviewThread:

[legend]Collaboration diagram for GeneratePreviewThread:

[legend]List of all members.

Public Member Functions
	GeneratePreviewThread (FilePreview *previewWidget)
void	start (QString filename)
virtual void	run ()
Private Attributes
QString	filename
	current file being processed
FilePreview *	previewWidget
	handle on preview widget necessary for posting an update event once the current file has been processed
bool	updating
	is the worker thread currently generating a file preview?
QString	queue
	next file to be processed by worker thread
QMutex	lockingMutex
	locking mutex - necessary to prevent multiple threads from accessing the updating bool or queue variable simultaniously

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Constructor & Destructor Documentation

GeneratePreviewThread::GeneratePreviewThread (  FilePreview *  previewWidget  )

Definition at line 60 of file addPhotosDialog.cpp. References queue, and updating. { //we'll need to store a previewWidget handle to //posting update events when updates are //ready to be shown this->previewWidget = previewWidget; //by default worker thread isn't busy yet updating = false; queue = QString::null; }

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Member Function Documentation

void GeneratePreviewThread::run (   )  [virtual]

Definition at line 94 of file addPhotosDialog.cpp. References filename, getImageSize(), lockingMutex, MIN_HEIGHT, MIN_WIDTH, previewWidget, queue, scaleImage(), and updating. { //since it is possible for another job //to be added to the queue while processing this one, it is necessary //to loop until the queue is empty while(true) { //------------------------------------------ //Get image type extension and convert to caps QString extension = QFileInfo(filename).extension(false).upper(); bool validExtension = ( (extension.compare("GIF") == 0) || (extension.compare("JPG") == 0) || (extension.compare("JPEG") == 0) || (extension.compare("PNG") == 0) || (extension.compare("XPM") == 0) ); //------------------------------------------ //Scale the image to fit nicely on the screen, aka < 300x225 QImage scaledImage; if( validExtension ) { scaleImage(filename, scaledImage, MIN_WIDTH, MIN_HEIGHT ); } //------------------------------------------ //Get image resolution QString imageRes = ""; if(validExtension) { QSize res; getImageSize( filename, res ); imageRes = QString("%1 x %2").arg(res.width()).arg(res.height()); } //------------------------------------------ //Determine file size and construct a nicely formatted size string QString fileSize = "?"; QFileInfo info; info.setFile( filename ); int sizeOnDisk = info.size(); if(sizeOnDisk < 1024) fileSize = QString("%1 Byte%2").arg(sizeOnDisk).arg( sizeOnDisk == 0 || sizeOnDisk > 1 ? "s" : ""); else if( sizeOnDisk/1024 < 1024) // fileSize = QString("%1 Kb").arg( ((float)*sizeOnDisk)/1024 ); fileSize = QString("%1 Kb").arg( ((float)((100*sizeOnDisk)/1024))/100 ); else if( sizeOnDisk/(1024*1024) < 1024) fileSize = QString("%1 Mb").arg( ((float)((100*sizeOnDisk)/(1024*1024)))/100 ); else fileSize = QString("%1 Gigs").arg( ((float)((100*sizeOnDisk)/(1024*1024*1024)))/100 ); //------------------------------------------ //Setup image details string QString fileDetails = QString("%1 %2, %3") .arg(imageRes) .arg(extension) .arg(fileSize); //------------------------------------------ //Post UPDATE_PREVIEW_DETAILS event UpdatePreviewEvent* upe = new UpdatePreviewEvent( scaledImage, fileDetails ); QApplication::postEvent( previewWidget, upe ); //------------------------------------------ //get lock lockingMutex.lock(); //if the queue is empty we're done! if( queue.isNull() ) { updating = false; lockingMutex.unlock(); return; } //clear queue and process pending job else { filename = queue; queue = QString::null; lockingMutex.unlock(); } } //end while(true) }

void GeneratePreviewThread::start (  QString  filename  )

Definition at line 72 of file addPhotosDialog.cpp. References lockingMutex, queue, and updating. Referenced by FilePreview::updatePreview(). { //get lock lockingMutex.lock(); //if currently animating then append job to queue if(updating) { queue = filename; lockingMutex.unlock(); return; } //else set animating to true, actually initiate job else { updating = true; this->filename = filename; lockingMutex.unlock(); QThread::start(); } }

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Member Data Documentation

QString GeneratePreviewThread::filename [private]

current file being processed Definition at line 38 of file addPhotosDialog.h. Referenced by run().

QMutex GeneratePreviewThread::lockingMutex [private]

locking mutex - necessary to prevent multiple threads from accessing the updating bool or queue variable simultaniously Definition at line 52 of file addPhotosDialog.h. Referenced by run(), and start().

FilePreview* GeneratePreviewThread::previewWidget [private]

handle on preview widget necessary for posting an update event once the current file has been processed Definition at line 42 of file addPhotosDialog.h. Referenced by run().

QString GeneratePreviewThread::queue [private]

next file to be processed by worker thread Definition at line 48 of file addPhotosDialog.h. Referenced by GeneratePreviewThread(), run(), and start().

bool GeneratePreviewThread::updating [private]

is the worker thread currently generating a file preview? Definition at line 45 of file addPhotosDialog.h. Referenced by GeneratePreviewThread(), run(), and start().

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The documentation for this class was generated from the following files:

• addPhotosDialog.h
• addPhotosDialog.cpp

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