Background for images with alpha channel
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This code makes the background red. It's important to call setAutoFillBackground(true) on the label, otherwise the background will not be changed!
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QPalette pal = ui->label->palette();
pal.setBrush(QPalette::Window, Qt::red);
ui->label->setPalette(pal);
ui->label->setAutoFillBackground(true);
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bq. Vass wrote
Gerolf It seems to me what I with you said about different things. As I understand samkpo has movie with alpha channel, and He want set background under this movie. You said about animate background for something with use Qmovie.But then you can just paint the background beffore drawing the move:
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void myWidgetClass::paintEvent(QPaintEvent*)
{
QPainter paint(this);
painter.draw... // draw the background here
paint.drawImage(rect(), myMove.currentImage());
}
@Or position a label or widget with the needed background exactly below the imageLabel. (so position one widget with setgeometry or make obne label a child of the other one). Or does QLabel not draw the movie with transparent background?
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nop, the palette stuff didn't work, when i call setMovie the background is gone, and even calling setBackgroundColor from QMovie doesn't work, so i've done something that fixes my problem, but in a way that isn't the better i guess.
@void ImageViewer::setGifImage()
{
QPixmap m = scuareBackground();
//m is an square 32x32, wich is the base for the alpha background.QPixmap temp(gifSize);
//create a pixmap qith the same size that the gif imageQPainter q(&temp);
q.drawTiledPixmap(0,0,gifSize.width(), gifSize.height(), m);
q.drawPixmap(0, 0, movie->currentPixmap());
q.end();imageLabel->setPixmap(temp);
}
@that's an slot i've made, and it's used in here:
@gifSize=(QPixmap(archivo->absoluteFilePath()).size());
movie->start();
connect(movie, SIGNAL(frameChanged(int)), this, SLOT(setGifImage()));//imageLabel->setMovie(movie);
imageLabel->resize(gifSize);@of course i have to make a lot of improvements but it's something.
if you have something to add or correct do it please
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If you go that way, I would suggest using the paintEvent, as you are creating a temporary image for each changed frame. Then you cans also derive the label (or from QWidget diretly) and implement thepaint event. Then connect the signal with update and it should work with less temporary objects / images.
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{
...
gifSize=(QPixmap(archivo->absoluteFilePath()).size());movie->start(); connect(movie, SIGNAL(frameChanged(int)), pImageLabel, SLOT(update())); //imageLabel->setMovie(movie); imageLabel->resize(gifSize); ...}
void CMyImageLabel::CMyImageLabel(QPixmap backSquare) :
m_squareBackground(backSquare)
{
}void CMyImageLabel::paintEvent()
{
QPainter paint(this);
paint.drawTiledPixmap(rect(), m_squareBackground);
paint.drawImage(rect(), myMove.currentImage());
}
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update is a "slot of QWidget":http://doc.trolltech.com/4.7/qwidget.html#update, right.
CMyImageLabel is a custom class, derived from QLabel or QWidget. If you need no functionality from QLabel (as you draw your image on your own) you can derive it from QWidget. Make the movie and the background image a member of the class. then connect the update slot and draw in the paintEvent.
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Volker, not exactly, i want to have:
- background color on my label
- a movie with transparency on top of the label
or
- an image on top of my label
- a movie with transparency on top of the image
i mean, it's not the color and the image together as backgrounds, it's the color or the image
Gerolf, ok, i think i understand
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samkpo, I made up my mind. You will have to make your own widget, as Gerolf supposed. Basically you have to reimplement the paintEvent:
movielabel.h
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#ifndef MOVIELABEL_H
#define MOVIELABEL_H#include <QWidget>
#include <QPixmap>
#include <QMovie>class MovieLabel : public QWidget
{
Q_OBJECT
public:
explicit MovieLabel(QWidget *parent = 0);signals:
public slots:
void start();
void setMovie(const QString &file);
void setBGPixmap(const QString &file);
void setBGColor(QColor c);void drawFrame(int frameNumber);protected:
void paintEvent(QPaintEvent *e);QMovie movie; QPixmap bgPixmap; QPixmap currentFrame;};
#endif // MOVIELABEL_H
@movielabel.cpp
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#include "movielabel.h"#include <QPainter>
#include <QPaintEvent>
#include <QDebug>MovieLabel::MovieLabel(QWidget *parent) :
QWidget(parent)
{
setAutoFillBackground(true);
connect(&movie, SIGNAL(frameChanged(int)), this, SLOT(drawFrame(int)));
}void MovieLabel::start()
{
movie.start();
}void MovieLabel::setMovie(const QString &file)
{
movie.setFileName(file);
}void MovieLabel::setBGPixmap(const QString &file)
{
bgPixmap.load(file);
}void MovieLabel::setBGColor(QColor c)
{
QPalette p = palette();
p.setColor(QPalette::Window, c);
setPalette(c);
}void MovieLabel::paintEvent(QPaintEvent *e)
{
if(bgPixmap.isNull())
QWidget::paintEvent(e);QPainter p(this); if(!bgPixmap.isNull()) p.drawPixmap(e->rect(), bgPixmap, e->rect()); p.drawPixmap(e->rect(), currentFrame, e->rect());}
void MovieLabel::drawFrame(int frameNumber)
{
currentFrame = movie.currentPixmap();
repaint();
}
@You will have to reimplement sizeHint and some more methods and insert some sanity checks for the movie and the pixmaps to make it a fully mature widget.