imageview.cc

c++的guiQt做的开发

void ImageView::updateFullScreen() {
 applyZoom();
}

/**
 Update data_rect
*/
void ImageView::setDataRect() {
 //Get image dimensions
 int dx=image->x();
 int dy=image->y();
 //Get image screen dimensions (may differ if zoom is set)
 int screen_dx=dx*zoom/100;
 int screen_dy=dy*zoom/100;
 int x=d->width();
 int y=d->height();
 int wx=x;
 int wy=dy*wx/dx;
 if (wy>y) {
  wy=y;
  wx=dx*wy/dy;
 }
 if (isSet("scale")) {
  if (!isSet("center")) {
   data_rect=QRect(0,0,wx,wy);
  } else {
   data_rect=QRect(max((x-wx)/2,0),max((y-wy)/2,0),wx,wy);
  }
 } else {
  if (!isSet("center")) {
   data_rect=QRect(0,0,screen_dx,screen_dy);
  } else {
   data_rect=QRect(max((x-screen_dx)/2,0),max((y-screen_dy)/2,0),screen_dx,screen_dy);
  }
 }
}

/**
 Repaint the image using given painter and size of output window
 @param x width of output window
 @param y height of output window
 @param p QPainter to use
 @param src Which part of image to repaint (when not in fullscreen)
*/
void ImageView::repaint(int x,int y,QPainter &p,const QRect &src) {
 if (isSet("antialias")) {
  //Set antialiasing
  p.setRenderHint(QPainter::SmoothPixmapTransform,true);
 }
 p.setPen(Qt::blue);
 QBrush black(QColor(0,0,0));
 if (!image) {
  //No image is loaded
  p.drawRect(0,0,x-1,y-1);
  p.fillRect(1,1,x-2,y-2,black);
  p.drawText(0,0,x,y,Qt::AlignVCenter | Qt::AlignCenter,tr("No image loaded"));
  return;
 }
 if (image->x()<=0 || image->y()<=0) {
  //Invalid image is loaded
  p.drawRect(0,0,x-1,y-1);
  p.fillRect(1,1,x-2,y-2,black);
  p.drawText(0,0,x,y,Qt::AlignVCenter | Qt::AlignCenter,tr("Invalid image"));
  return;
 }
 //Rectangle specifying entire window
 QRect wnd=QRect(0,0,x,y);
 //Determine target rectangle at screen
 //Update data rectangle for mouse navigation
 setDataRect();
 //Repaint stripes around image if needed
 if (data_rect.left()>src.left()) {
  //repaint stripe on left
  QRect tmp(0,0,data_rect.left(),y);
  p.fillRect(tmp & src,black);
 }
 if (data_rect.right()<src.right()) {
  //repaint on right
  QRect tmp(data_rect.right(),0,x-data_rect.right(),y);
  p.fillRect(tmp & src,black);
 }
 if (data_rect.top()>src.top()) {
  //repaint on top
  QRect tmp(data_rect.left(),0,data_rect.width(),data_rect.top());
  p.fillRect(tmp & src,black);
 }
 if (data_rect.bottom()<src.bottom()) {
  //repaint on bottom
  QRect tmp(data_rect.left(),data_rect.bottom(),data_rect.width(),y-data_rect.bottom());
  p.fillRect(tmp & src,black);
 }
 if (isSet("scale")) {  //Show scaled to window
  //Set target to data rectangle
  QRect target=data_rect;
  //Draw entire image scaled
  QRect source(0,0,image->x(),image->y());
  image->draw(&p,source,target);
 } else {
  //No scaling - show 1:1 or show with arbitrary zoom
  //Cut out anything outside the actual image
  QRect target=src & data_rect;
  if (!target.isEmpty()) {  //Is there anything left to draw?
   if (zoom==100) {
    //No resizing - copy the image
    int ix=target.left()-data_rect.left();
    int iy=target.top()-data_rect.top();
    int isx=target.width();
    int isy=target.height();
    QRect source(ix,iy,isx,isy);
    //Paint it
    image->draw(&p,source,target);
   } else {
//#if QT_VERSION < 0x040200
    //Partial workaround for rounding errors (QT 4.1.x or earlier)
    target.setWidth(target.width()+1);
    target.setHeight(target.height()+1);
    target=target & data_rect;
//#endif
    //Draw part of image
    double fx=(double)(target.left()-data_rect.left())*100.0/(double)zoom;
    double fy=(double)(target.top()-data_rect.top())*100.0/(double)zoom;
    double fsx=(double)target.width()*100.0/(double)zoom;
    double fsy=(double)target.height()*100.0/(double)zoom;
//    cout << fx << "," << fy << " " << fsx << "x" << fsy << endl;
/*
#if QT_VERSION >= 0x040200
    QRect sourcebound((int)floor(fx),(int)floor(fy),(int)ceil(fsx),(int)ceil(fsy));
    //This code is correct in Qt4.2. Qt4.1 can't work with subpixel precision on input
    QRectF source(fx,fy,fsx,fsy);
    //Paint it
    image->draw(&p,sourcebound,target,source);
#else
*/
    //Workaround for QT 4.1.x
    //This code is "most correct"
    QRect sourcebound((int)floor(fx),(int)floor(fy),(int)ceil(fsx+frac(fx)),(int)ceil(fsy+frac(fy)));
    //Recalculate target from sourcebound (to avoid painting non-integer number of pixels from source)
    target.setLeft(sourcebound.left()*zoom/100+data_rect.left());
    target.setTop(sourcebound.top()*zoom/100+data_rect.top());
    target.setWidth(sourcebound.width()*zoom/100);
    target.setHeight(sourcebound.height()*zoom/100);
    target=target & data_rect;
    //Paint it
    image->draw(&p,sourcebound,target);

    //Perfectly accurate, but insanely slow solution
    //QRect source(0,0,dx,dy);
    //p.setClipRect(target);
    //image->draw(&p,source,data_rect);
//#endif

   }
  }
 }
}

/**
 Cancel any picks (coordinates, pixel intensity) that may be in progress
 Should be called before setting any picking mode and setting up own signal for it
 */
void ImageView::cancelPicks() {
 if (mode==view) return; //nothing to cancel
 emit cancelledPick();
 setMode(view);
}

/**
 Scroll the area by x pixels down and y pixels to the right
 @param x How many pixels to sroll to down
 @param y How many pixels to sroll to right
*/
void ImageView::scrollBy(int x,int y) {
 QScrollBar *h=horizontalScrollBar();
 QScrollBar *v=verticalScrollBar();
 h->setValue(h->value()+x);
 v->setValue(v->value()+y);
}

/**
 Handler called when key is pressed
 @param e event data
*/
void ImageView::keyPressEvent(QKeyEvent *e) {
 if (image) {
  int key=e->key();
  switch (key) {
   case Qt::Key_Escape:
    cancelPicks();
    break;
   case Qt::Key_Up:
    scrollBy(0,-16);
    break;
   case Qt::Key_Down:
    scrollBy(0,16);
    break;
   case Qt::Key_Left:
    scrollBy(-16,0);
    break;
   case Qt::Key_Right:
    scrollBy(16,0);
    break;
   case Qt::Key_Home:
    scrollBy(-QWIDGETSIZE_MAX,0);
    break;
   case Qt::Key_End:
    scrollBy(QWIDGETSIZE_MAX,0);
    break;
   case Qt::Key_PageUp:
    scrollBy(0,-height());
    break;
   case Qt::Key_PageDown:
    scrollBy(0,height());
    break;
   case '+':
   case '=':
    zoomStep(true);
    break;
   case '-':
    zoomStep(false);
    break;
   default:
    return;
  }
  return;
 }
 e->ignore();
}

/**
 Changes zoom to given percentage
 @param nzoom New zoom, in percent
*/
void ImageView::setZoom(int nzoom) {
 zoom=nzoom;
 applyZoom();
}

/**
 Fix zoom value to be within allowed limits and apply new zoom value
*/
void ImageView::applyZoom() {
 if (zoom<MIN_ZOOM) zoom=MIN_ZOOM;
 if (zoom>MAX_ZOOM) zoom=MAX_ZOOM;
 update();//Will update data_rect
 if (selection.isValid()) {
  setDataRect();
  d->moveRubberBand(selectionFromImageCoords(selection));
 }
 emit zoomChanged(zoom);
}

/**
 Changes zoom in given direction
 @param steps Number of steps to zoom in (positive) or out (negative)
*/
void ImageView::zoomSteps(int steps) {
 if (!steps) return; //Zero?
 while (steps<0) { // Zoom -N
  zoomStepInternal(false);
  steps++;
  if (zoom<MIN_ZOOM) break;//Too much zoom
 }
 while (steps>0) { // Zoom +N
  zoomStepInternal(true);
  steps--;
  if (zoom>MAX_ZOOM) break;//Too much zoom
 }
 applyZoom();
}

/**
 Changes zoom in given direction
 @param zoomIn True if zoom in, else zoom out
*/
void ImageView::zoomStep(bool zoomIn) {
 zoomStepInternal(zoomIn);
 applyZoom();
}

/**
 Changes zoom in given direction without applying it
 @param zoomIn True if zoom in, else zoom out
*/
void ImageView::zoomStepInternal(bool zoomIn) {
 int step=10;
 if (!zoomIn) {
  if (zoom<=50) step=5;
  if (zoom<=20) step=2;
  if (zoom<=10) step=1;
  if (zoom>200) step=25;
  if (zoom>500) step=100;
  if (zoom>1000) step=200;
  if (zoom>2000) step=500;
  zoom-=step;
 } else {
  if (zoom<50) step=5;
  if (zoom<20) step=2;
  if (zoom<10) step=1;
  if (zoom>=200) step=25;
  if (zoom>=500) step=100;
  if (zoom>=1000) step=200;
  if (zoom>=2000) step=500;
  zoom+=step;
 }
}

/**
 Handler called when key is released
 @param e event data
*/
void ImageView::keyReleaseEvent(QKeyEvent *e) {
 e->ignore();
}

/**
 Handler called when mouse is moved over the widget
 @param e event data
*/
void ImageView::mouseMoveEvent(QMouseEvent *e) {
 if (!image) {
  e->ignore();
  return;
 }
 int mx=e->x();
 int my=e->y();
 if (e->buttons() & Qt::RightButton) {
  //right mouse button pressed
  scrollBy(mouse_ex-mx,mouse_ey-my);
  mouse_ex=mx;
  mouse_ey=my;
 }
}

/**
 Return string representation of channel count
 @param c number of channels
*/
QString ImageView::channelsToString(int c) {
 if (c==1) return "L";		//luminosity (greyscale)
 if (c==2) return "LA";		//luminosity (greyscale)+alpha
 if (c==3) return "RGB";	//RGB
 if (c==4) return "RGBA";	//RGB+Alpha
 return QString("(%1C)").arg(c);
}

/**
 Handler called when mouse is moved over the widget
 @param e event data
*/
void ImageView::mouseCoordEvent(QMouseEvent *e) {
 if (!image) {
  e->ignore();
  return;
 }
 int mx=e->x();
 int my=e->y();
 QString value="";
 if (!(mx<data_rect.x() || my<data_rect.y() || mx>data_rect.right() || my>data_rect.bottom())) {
  // Mouse move within the image
  mx-=data_rect.x();
  my-=data_rect.y();
  mouse_x=mx*image->x()/data_rect.width();
  mouse_y=my*image->y()/data_rect.height();
  int c=image->channels();
  value=channelsToString(c);
  value+="="; 
  for (int i=0;i<c;i++) {
   //Image values
   value+=QString::number(image->value(mouse_x,mouse_y,i));
   if (i<c-1) value+=",";
  }
  value+=" (#";
  for (int i=0;i<c;i++) {
   //Image values in hex
   value+=image->valueHex(mouse_x,mouse_y,i);  
  }
  value+=")";
  //Mouse coords
  value=QString("[")+QString::number(mouse_x)+","+QString::number(mouse_y)+"] "+value;
 }
 if (!selectionText.isNull()) {
  emit selectionInfo(selectionText);
 } else {
  emit selectionInfo("");
 }
 emit info(value);
}

/**
 Mouse press handler
 @param e event data
 */
void ImageView::mousePressEvent(QMouseEvent *e) {
 if (!image) {
  e->ignore();
  return;
 }
 if (e->button()==Qt::LeftButton) {
  if (mode==crosshair) {
   setMode(view);
   return;
  }
 }
 if (e->button()==Qt::RightButton) {
#if QT_VERSION >= 0x040200
  //Only Qt 4.2 or newer
  d->setCursor(Qt::ClosedHandCursor);
#else
  d->setCursor(Qt::SizeAllCursor);
#endif
  mouse_ex=e->x();
  mouse_ey=e->y();
 } else {
  e->ignore();
 }
}

/**
 Handler called when one of the mouse buttons is released
 @param e event data
*/
void ImageView::mouseReleaseEvent(QMouseEvent *e) {
 // "reset" current mode
 setMode(mode);
 e->ignore();
}

/**
 Handler called when wheel on the mouse is scrolled
 @param e event data
*/
void ImageView::wheelEvent (QWheelEvent *e) {
 if (!image) return;
 int z=e->delta()/4;
 scrollBy(0,-z);
 update();
}

/** default destructor */
ImageView::~ImageView() {
 if (image) delete image;
}

} // namespace gui