Background for images with alpha channel

giesbert

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.

@
{
...
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());
}
@

samkpo

Volker, i want to set both image and color.

Gerolf, thanks for the improved code, and now i have two questions: the slot update() is from QWidget? (remember i said i was learning) and, can you explain better what is CMyImageLabel?

goetz

samkpo, ok if I understand you right you have

background color (e.g. red) on your lebel
a semi-background image with transparency on top of the background color
a movie with transparency on top of the semi-background image

Am I right?

giesbert

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.

samkpo

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

goetz

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

@
#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
@
#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.

samkpo

ok guys, thanks a lot, i'll let you know when i finish it.

goetz

[quote author="samkpo" date="1292799006"]ok guys, thanks a lot, i'll let you know when i finish it.[/quote]

Good luck!