HistogramInterface Class Reference

#include <histogramInterface.h>

Inheritance diagram for HistogramInterface:

Collaboration diagram for HistogramInterface:

Signals
void	selectedRangeChanged ()

Public Member Functions
	HistogramInterface (QString imageFilename, QWidget *parent=0, const char *name=0)
	Creates layout.
	~HistogramInterface ()
	Deletes objects.
void	setDisplayChannel (DISPLAYED_CHANNEL channel)
	Sets currently displayed channel.
virtual QSize	minimumSizeHint () const
void	getHistBoundaries (int &lumLeft, int &lumRight, int &redLeft, int &redRight, int &greenLeft, int &greenRight, int &blueLeft, int &blueRight)
	returns histogram boundaries
void	resetBoundaries ()
	resets all boundaries

Protected Member Functions
void	paintEvent (QPaintEvent *e)
void	resizeEvent (QResizeEvent *)
void	mousePressEvent (QMouseEvent *e)
void	mouseReleaseEvent (QMouseEvent *)
void	mouseMoveEvent (QMouseEvent *e)

Private Slots
void	selectAll ()

Private Member Functions
void	getSelectedRange (int &left, int &right)
	this utility function finds currently selected range
double	displayToIndex (int val)
	convert screen coordinate to index in 0-255 range
int	indexToDisplay (int val)
	converts index in 0-255 ranges to screen coordinate
bool	nearBoundary (QPoint p)
	determines if mouse is near boundary

Private Attributes
DISPLAYED_CHANNEL	displayedChannel
	Currently displayed channel.
int	redVals [256]
	color and luminosity histograms
int	greenVals [256]
int	blueVals [256]
int	grayVals [256]
int	maxRcount
	max r,g,b, and gray counts
int	maxGcount
int	maxBcount
int	maxGRAYcount
int	lumClick
	left and right bounds for each channel
int	lumDrag
int	redClick
int	redDrag
int	greenClick
int	greenDrag
int	blueClick
int	blueDrag
QSize	origImageSize
	original image dimensions, needed for painting
DRAG_MODE	dragMode
	effect of mouse drags
DRAG_MODE	currentMouseShape
	current mouse shape.

Detailed Description

Definition at line 44 of file histogramInterface.h.

Constructor & Destructor Documentation

HistogramInterface()

HistogramInterface::HistogramInterface	(	QString	imageFilename,
		QWidget *	parent = 0,
		const char *	name = 0 )

Creates layout.

add keybinding for selecting entire range

Definition at line 41 of file histogramInterface.cpp.

                                                                            : 
                                        QWidget (parent, name, Qt::WNoAutoErase)
{                     
  //set default mode to adjusted image
  displayedChannel = LUMINOSITY;
  
  //record original image width and height
  getImageSize( imageFilename, origImageSize );
  
  //construct histogram for color and luminosity channels
  //resize image to current screen size for faster
  //scaling during resize events
  QRect screenSize = qApp->desktop()->availableGeometry();
  QImage image;
  scaleImage( imageFilename, image, screenSize.width()/4, screenSize.height()/4 );
 
  int i;
  for(i=0; i<256; i++)
  {    
    redVals[i] = 0;
    greenVals[i] = 0;
    blueVals[i] = 0;
    grayVals[i] = 0;
  }
  int x, y;
  QRgb* rgb;
  uchar* scanLine;
  for( y=0; y<image.height(); y++)
  {   
    scanLine = image.scanLine(y);
    for( x=0; x<image.width(); x++)
    {
      rgb = ((QRgb*)scanLine+x);
      redVals[ qRed(*rgb) ]++;
      greenVals[ qGreen(*rgb) ]++; 
      blueVals[ qBlue(*rgb) ]++;
      grayVals[ qGray(*rgb) ]++;
    } //x
  } //y
  
  //find max r,g,b, and gray counts
  maxRcount = 0;
  maxGcount = 0;
  maxBcount = 0;
  maxGRAYcount = 0;
  for(i=0; i<256; i++)
  {
    if(redVals[i]   > maxRcount)    maxRcount    = redVals[i]; 
    if(greenVals[i] > maxGcount)    maxGcount    = greenVals[i]; 
    if(blueVals[i]  > maxBcount)    maxBcount    = blueVals[i]; 
    if(grayVals[i]  > maxGRAYcount) maxGRAYcount = grayVals[i]; 
  }
  //----          
  //by default mouse drags have no effect
  dragMode = NO_EFFECT;
  currentMouseShape = NO_EFFECT;
 
  //watch mouse movements in order to drag selection
  setMouseTracking(true);
  
  //accept focus when clicked on
  setFocusPolicy( Qt::ClickFocus );  
 
  Q3Accel *keyAccel = new Q3Accel( this );
  keyAccel->connectItem( keyAccel->insertItem( Qt::CTRL + Qt::Key_A),
                         this, SLOT(selectAll()) );  
  
  //default cursor is cross hair indication regions can be selected
  setCursor( getCursor(CROSS_CURSOR) );
  
  //by default entire range is selected for all channels
  resetBoundaries();
}

References blueVals, CROSS_CURSOR, currentMouseShape, displayedChannel, dragMode, getCursor(), getImageSize(), grayVals, greenVals, LUMINOSITY, maxBcount, maxGcount, maxGRAYcount, maxRcount, NO_EFFECT, origImageSize, redVals, resetBoundaries(), scaleImage(), and selectAll().

~HistogramInterface()

HistogramInterface::~HistogramInterface

(

)

Deletes objects.

Definition at line 117 of file histogramInterface.cpp.

{ }

Member Function Documentation

displayToIndex()

double HistogramInterface::displayToIndex ( int val )

private

convert screen coordinate to index in 0-255 range

Definition at line 150 of file histogramInterface.cpp.

{
  return (255.0*coordinate) / ( width()-1 );
}

References width.

Referenced by mouseMoveEvent(), mousePressEvent(), nearBoundary(), and paintEvent().

getHistBoundaries()

void HistogramInterface::getHistBoundaries	(	int &	lumLeft,
		int &	lumRight,
		int &	redLeft,
		int &	redRight,
		int &	greenLeft,
		int &	greenRight,
		int &	blueLeft,
		int &	blueRight )

returns histogram boundaries

Definition at line 439 of file histogramInterface.cpp.

{
  lumLeft = QMIN( lumClick, lumDrag );
  lumRight = QMAX( lumClick, lumDrag );
 
  redLeft = QMIN( redClick, redDrag );
  redRight = QMAX( redClick, redDrag );
 
  greenLeft = QMIN( greenClick, greenDrag );
  greenRight = QMAX( greenClick, greenDrag );
 
  blueLeft = QMIN( blueClick, blueDrag );
  blueRight = QMAX( blueClick, blueDrag );
}

References blueClick, blueDrag, greenClick, greenDrag, lumClick, lumDrag, redClick, and redDrag.

Referenced by HistogramEditor::adjustImage(), HistogramEditor::applyAction(), and HistogramEditor::getHistBoundaries().

getSelectedRange()

void HistogramInterface::getSelectedRange ( int & left, int & right )

private

this utility function finds currently selected range

Definition at line 124 of file histogramInterface.cpp.

{
  if(displayedChannel == LUMINOSITY) 
  {
    left = QMIN( lumClick, lumDrag );
    right = QMAX( lumClick, lumDrag );
  }
  else if(displayedChannel == RED)   
  { 
    left = QMIN( redClick, redDrag );
    right = QMAX( redClick, redDrag );
  }
  else if(displayedChannel == GREEN) 
  { 
    left = QMIN( greenClick, greenDrag );
    right = QMAX( greenClick, greenDrag );
  }
  else if(displayedChannel == BLUE)  
  { 
    left = QMIN( blueClick, blueDrag );
    right = QMAX( blueClick, blueDrag );
  }   
  else
  { left = 0; right = 0; }
}

References BLUE, blueClick, blueDrag, displayedChannel, GREEN, greenClick, greenDrag, lumClick, lumDrag, LUMINOSITY, RED, redClick, and redDrag.

Referenced by mouseMoveEvent(), mousePressEvent(), nearBoundary(), paintEvent(), and selectAll().

indexToDisplay()

int HistogramInterface::indexToDisplay ( int val )

private

converts index in 0-255 ranges to screen coordinate

Definition at line 155 of file histogramInterface.cpp.

{
  return (index* (width()-1) ) / 255;
}

References width.

Referenced by paintEvent().

minimumSizeHint()

QSize HistogramInterface::minimumSizeHint ( ) const

virtual

Definition at line 291 of file histogramInterface.cpp.

{
  return QSize( 256,100 + COLOR_BAR_MARGIN + 2*COLOR_BAR_BORDER + COLOR_BAR_HEIGHT );
}

References COLOR_BAR_BORDER, COLOR_BAR_HEIGHT, and COLOR_BAR_MARGIN.

mouseMoveEvent()

void HistogramInterface::mouseMoveEvent ( QMouseEvent * e )

protected

Definition at line 373 of file histogramInterface.cpp.

{
  //if not dragging a selection then update mouse cursor as appropriate
  if(dragMode == NO_EFFECT)
  {
    if( nearBoundary(e->pos()) && currentMouseShape == NO_EFFECT )
    {
      currentMouseShape = DRAG;
      setCursor( getCursor(MOVE_HOR_CURSOR) );
    }
    else if( !nearBoundary(e->pos()) && currentMouseShape == DRAG )
    { 
      currentMouseShape = NO_EFFECT;
      setCursor( getCursor(CROSS_CURSOR) );
    }
 
    return;
  }
  
  //compute index in 0-255 range from mouse coordinates
  int x = QMAX( QMIN( e->pos().x(), width()-1 ), 0 );
  int index = (int) displayToIndex( x );
 
  //reset boundary
  if(displayedChannel == LUMINOSITY) { lumDrag = index; }
  else if(displayedChannel == RED)   { redDrag = index; }
  else if(displayedChannel == GREEN) { greenDrag = index; }
  else if(displayedChannel == BLUE)  { blueDrag = index; }          
  
  //repaint
  repaint(false);  
  
  //emit selectection changed signal
  int left, right;
  getSelectedRange( left, right );
  emit selectedRangeChanged();    
}

References BLUE, blueDrag, CROSS_CURSOR, currentMouseShape, displayedChannel, displayToIndex(), DRAG, dragMode, getCursor(), getSelectedRange(), GREEN, greenDrag, lumDrag, LUMINOSITY, MOVE_HOR_CURSOR, nearBoundary(), NO_EFFECT, RED, redDrag, selectedRangeChanged(), and width.

mousePressEvent()

void HistogramInterface::mousePressEvent ( QMouseEvent * e )

protected

Definition at line 312 of file histogramInterface.cpp.

{
  //begin drag mode!
  dragMode = DRAG;
 
  //compute index from mouse position
  int index = (int) displayToIndex( e->pos().x() );
      
  //get left and right to check for clicks near current boundaries
  int left, right;
  getSelectedRange( left, right );
 
  //get click and drag handles
  int *click, *drag;
  if(displayedChannel == LUMINOSITY) 
  { 
    click = &lumClick; drag = &lumDrag; 
  }
  else if(displayedChannel == RED)   
  { 
    click = &redClick; drag = &redDrag; 
  }
  else if(displayedChannel == GREEN) 
  { 
    click = &greenClick; drag = &greenDrag; 
  }
  else
  { 
    click = &blueClick; drag = &blueDrag; 
  }
    
  //if within threshold of left then start dragging that side
  if( index < left + DRAG_THRESHOLD &&
      index > left - DRAG_THRESHOLD )
  {
    *click = right;
    *drag = left;
    return;
  }
  //if within threshold of left then start dragging that side
  if( index < right + DRAG_THRESHOLD &&
      index > right - DRAG_THRESHOLD )
  {
    *click = left;
    *drag = right;
    return;
  }
  //else begin new drag
  else
  {
    *click = index;
    *drag = index;
    repaint(false);
 
    //emit selectection changed signal
    int left, right;
    getSelectedRange( left, right );
    emit selectedRangeChanged();    
  }
}

References blueClick, blueDrag, displayedChannel, displayToIndex(), DRAG, DRAG_THRESHOLD, dragMode, getSelectedRange(), GREEN, greenClick, greenDrag, lumClick, lumDrag, LUMINOSITY, RED, redClick, redDrag, and selectedRangeChanged().

mouseReleaseEvent()

void HistogramInterface::mouseReleaseEvent ( QMouseEvent * e )

protected

Definition at line 411 of file histogramInterface.cpp.

{
  //set mouse drags to no longer have any effect on boundary
  dragMode = NO_EFFECT;
 
  //update mouse cursor if necessary
  if( !nearBoundary(e->pos()) && currentMouseShape == DRAG )
  { 
    currentMouseShape = NO_EFFECT;
    setCursor( getCursor(CROSS_CURSOR) );
  }    
}

References CROSS_CURSOR, currentMouseShape, DRAG, dragMode, getCursor(), nearBoundary(), and NO_EFFECT.

nearBoundary()

bool HistogramInterface::nearBoundary ( QPoint p )

private

determines if mouse is near boundary

Definition at line 296 of file histogramInterface.cpp.

{
  //compute index from mouse position
  int index = (int) displayToIndex( p.x() );
  
  //get left and right to check for clicks near current boundaries
  int left, right;
  getSelectedRange( left, right );
 
  //check if within threshold of left or right boundaries
  return ( (index < left + 1 + DRAG_THRESHOLD &&
            index > left -     DRAG_THRESHOLD) ||
           (index < right + DRAG_THRESHOLD &&
            index > right - 1 - DRAG_THRESHOLD) );
}

References displayToIndex(), DRAG_THRESHOLD, and getSelectedRange().

Referenced by mouseMoveEvent(), and mouseReleaseEvent().

paintEvent()

void HistogramInterface::paintEvent ( QPaintEvent * e )

protected

Definition at line 160 of file histogramInterface.cpp.

{ 
  //create buffer to draw in
  QPixmap buffer( size() );
  buffer.fill( Qt::white );
  
  //create a painter pointing to the buffer
  QPainter bufferPainter( &buffer );
  
  //turn off clipping to make painting operations faster
  bufferPainter.setClipping(false);
 
  //initialize buffer with background brush
  bufferPainter.fillRect( buffer.rect(), backgroundBrush() );
 
  //get handle on histogram data, get max count, set default draw color, and find
  //left and right boundaries of current selection  
  QColor color = Qt::black;
  int* data = grayVals;
  int maxCount = maxGRAYcount;
 
  if(displayedChannel == RED)        { data = redVals;   color = Qt::red;   maxCount = maxRcount; }
  else if(displayedChannel == GREEN) { data = greenVals; color = Qt::green; maxCount = maxGcount; }
  else if(displayedChannel == BLUE)  { data = blueVals;  color = Qt::blue;  maxCount = maxBcount; }
  
  int indexLeft, indexRight;
  getSelectedRange(indexLeft,indexRight);
  int displayLeft = indexToDisplay ( indexLeft );
  int displayRight = indexToDisplay ( indexRight );  
 
  int histogramHeight = HISTOGRAM_HEIGHT;
  
  //iterate over each pixel column
  int x;
  for(x=0; x<width(); x++)
  {    
    double index = displayToIndex( x );
    int indexL = (int)index;
    double scaleR = index - indexL;
    
    int h = 0;
    if(indexL < 255)
    { 
      h = (int) ((1-scaleR)*data[indexL] + scaleR*data[indexL+1]); 
    }
    else 
    { 
      h = data[255]; 
    }
 
    //scale count so that the maxCount maps to the maximum height
    double scaledH = (histogramHeight*h)/maxCount;
    h = (int) scaledH;    
    //round up values between 0 and 1 so show data is there
    if( h == 0 && scaledH > h) h++;
    
    if(h > 0)
    {
      //use a gray color outside selected range
      QColor usedColor = color;
      if(x < displayLeft || x > displayRight) { usedColor = Qt::gray; }
        
      bufferPainter.fillRect( QRect(x, histogramHeight - h, 
                                    1, h),
                              QBrush(usedColor) );    
    }
    
    //if this is left or right boundary of selection and entire range not selected then
    //draw a vertical black line to make it stand out more
    if( (x == displayLeft || x == displayLeft+1 ||
         x == displayRight || x == displayRight-1) )
    {
      bufferPainter.drawLine( x, 0, x, histogramHeight-1 );
    }
  }
  //----
  //paint color bar key below
  
  //first a black border
  bufferPainter.fillRect( QRect(0, histogramHeight + COLOR_BAR_MARGIN, 
                                width(), COLOR_BAR_HEIGHT+2*COLOR_BAR_BORDER),
                          QBrush(Qt::black) );    
 
  //next the color gradient
  QColor scaledColor;
  for(x=COLOR_BAR_BORDER; x < width()-COLOR_BAR_BORDER; x++)
  {    
    int index;
    if(x <= displayLeft )
      index = 0;
    else if(x >= displayRight)
      index = 255;
    else
      index = (int) (255.0*(x-displayLeft))/(displayRight - displayLeft);
  
    int r = color.red();
    int g = color.green();
    int b = color.blue();
    
    if( r != 0) r = index;
    if( g != 0) g = index;
    if( b != 0) b = index;
    
    //black color was used when adjusting luminance, scale to white instead (since black is 0)
    if( color == Qt::black )
    { r = g = b = index; }
 
    scaledColor.setRgb( r,g,b );
    bufferPainter.fillRect( QRect(x, histogramHeight + COLOR_BAR_MARGIN + COLOR_BAR_BORDER, 
                                  1, COLOR_BAR_HEIGHT),
                            QBrush(scaledColor) );    
  }    
    
  //end painter  
  bufferPainter.end();
  
  //blit buffer to screen
  bitBlt( this,
          e->rect().x(), e->rect().y(),
          &buffer, 
          e->rect().x(), e->rect().y(),
          e->rect().width(), e->rect().height() );
}

References b, BLUE, blueVals, buffer, COLOR_BAR_BORDER, COLOR_BAR_HEIGHT, COLOR_BAR_MARGIN, displayedChannel, displayToIndex(), getSelectedRange(), grayVals, GREEN, greenVals, HISTOGRAM_HEIGHT, indexToDisplay(), maxBcount, maxGcount, maxGRAYcount, maxRcount, RED, redVals, and width.

resetBoundaries()

void HistogramInterface::resetBoundaries

(

)

resets all boundaries

Definition at line 457 of file histogramInterface.cpp.

{
  lumClick = redClick = greenClick = blueClick = 0; 
  lumDrag = redDrag = greenDrag = blueDrag = 255;  
  repaint(false);
  emit selectedRangeChanged();    
}

References blueClick, blueDrag, greenClick, greenDrag, lumClick, lumDrag, redClick, redDrag, and selectedRangeChanged().

Referenced by HistogramInterface(), and HistogramEditor::resetAction().

resizeEvent()

void HistogramInterface::resizeEvent ( QResizeEvent * )

protected

Definition at line 119 of file histogramInterface.cpp.

{  
  repaint(false);
}

selectAll

void HistogramInterface::selectAll ( )

privateslot

Definition at line 424 of file histogramInterface.cpp.

{
  //reset boundary
  if(displayedChannel == LUMINOSITY) { lumClick = 0,   lumDrag = 255;   }
  else if(displayedChannel == RED)   { redClick = 0;   redDrag = 255;   }
  else if(displayedChannel == GREEN) { greenClick = 0; greenDrag = 255; }
  else if(displayedChannel == BLUE)  { blueClick = 0;  blueDrag = 255;  } 
  repaint(false);  
 
  //emit selectection changed signal
  int left, right;
  getSelectedRange( left, right );
  emit selectedRangeChanged();    
}

References BLUE, blueClick, blueDrag, displayedChannel, getSelectedRange(), GREEN, greenClick, greenDrag, lumClick, lumDrag, LUMINOSITY, RED, redClick, redDrag, and selectedRangeChanged().

Referenced by HistogramInterface().

selectedRangeChanged

void HistogramInterface::selectedRangeChanged ( )

signal

Referenced by mouseMoveEvent(), mousePressEvent(), resetBoundaries(), and selectAll().

setDisplayChannel()

void HistogramInterface::setDisplayChannel

(

DISPLAYED_CHANNEL

channel

)

Sets currently displayed channel.

Definition at line 284 of file histogramInterface.cpp.

{
  //set mode and repaint
  displayedChannel = channel;
  repaint(false);
}

References displayedChannel.

Referenced by HistogramEditor::selectHistogramType().

Member Data Documentation

blueClick

int HistogramInterface::blueClick

private

Definition at line 114 of file histogramInterface.h.

Referenced by getHistBoundaries(), getSelectedRange(), mousePressEvent(), resetBoundaries(), and selectAll().

blueDrag

int HistogramInterface::blueDrag

private

Definition at line 114 of file histogramInterface.h.

Referenced by getHistBoundaries(), getSelectedRange(), mouseMoveEvent(), mousePressEvent(), resetBoundaries(), and selectAll().

blueVals

int HistogramInterface::blueVals[256]

private

Definition at line 104 of file histogramInterface.h.

Referenced by HistogramInterface(), and paintEvent().

currentMouseShape

DRAG_MODE HistogramInterface::currentMouseShape

private

current mouse shape.

by caching this value we avoid resetting the mouse cursor every time it moves etc.

Definition at line 124 of file histogramInterface.h.

Referenced by HistogramInterface(), mouseMoveEvent(), and mouseReleaseEvent().

displayedChannel

DISPLAYED_CHANNEL HistogramInterface::displayedChannel

private

Currently displayed channel.

Definition at line 99 of file histogramInterface.h.

Referenced by getSelectedRange(), HistogramInterface(), mouseMoveEvent(), mousePressEvent(), paintEvent(), selectAll(), and setDisplayChannel().

dragMode

DRAG_MODE HistogramInterface::dragMode

private

effect of mouse drags

Definition at line 120 of file histogramInterface.h.

Referenced by HistogramInterface(), mouseMoveEvent(), mousePressEvent(), and mouseReleaseEvent().

grayVals

int HistogramInterface::grayVals[256]

private

Definition at line 105 of file histogramInterface.h.

Referenced by HistogramInterface(), and paintEvent().

greenClick

int HistogramInterface::greenClick

private

Definition at line 113 of file histogramInterface.h.

Referenced by getHistBoundaries(), getSelectedRange(), mousePressEvent(), resetBoundaries(), and selectAll().

greenDrag

int HistogramInterface::greenDrag

private

Definition at line 113 of file histogramInterface.h.

Referenced by getHistBoundaries(), getSelectedRange(), mouseMoveEvent(), mousePressEvent(), resetBoundaries(), and selectAll().

greenVals

int HistogramInterface::greenVals[256]

private

Definition at line 103 of file histogramInterface.h.

Referenced by HistogramInterface(), and paintEvent().

lumClick

int HistogramInterface::lumClick

private

left and right bounds for each channel

Definition at line 111 of file histogramInterface.h.

Referenced by getHistBoundaries(), getSelectedRange(), mousePressEvent(), resetBoundaries(), and selectAll().

lumDrag

int HistogramInterface::lumDrag

private

Definition at line 111 of file histogramInterface.h.

Referenced by getHistBoundaries(), getSelectedRange(), mouseMoveEvent(), mousePressEvent(), resetBoundaries(), and selectAll().

maxBcount

int HistogramInterface::maxBcount

private

Definition at line 108 of file histogramInterface.h.

Referenced by HistogramInterface(), and paintEvent().

maxGcount

int HistogramInterface::maxGcount

private

Definition at line 108 of file histogramInterface.h.

Referenced by HistogramInterface(), and paintEvent().

maxGRAYcount

int HistogramInterface::maxGRAYcount

private

Definition at line 108 of file histogramInterface.h.

Referenced by HistogramInterface(), and paintEvent().

maxRcount

int HistogramInterface::maxRcount

private

max r,g,b, and gray counts

Definition at line 108 of file histogramInterface.h.

Referenced by HistogramInterface(), and paintEvent().

origImageSize

QSize HistogramInterface::origImageSize

private

original image dimensions, needed for painting

Definition at line 117 of file histogramInterface.h.

Referenced by HistogramInterface().

redClick

int HistogramInterface::redClick

private

Definition at line 112 of file histogramInterface.h.

Referenced by getHistBoundaries(), getSelectedRange(), mousePressEvent(), resetBoundaries(), and selectAll().

redDrag

int HistogramInterface::redDrag

private

Definition at line 112 of file histogramInterface.h.

Referenced by getHistBoundaries(), getSelectedRange(), mouseMoveEvent(), mousePressEvent(), resetBoundaries(), and selectAll().

redVals

int HistogramInterface::redVals[256]

private

color and luminosity histograms

Definition at line 102 of file histogramInterface.h.

Referenced by HistogramInterface(), and paintEvent().

---

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

• histogramInterface.h
• histogramInterface.cpp