QImage, PNG ad Transparency

[Rebe]

Hi!

I'm new to the forum and quite new to the Qt Programming.

I've a problem with QImage.
I need to draw an image (.png) with transparency.
I've serched and read a lot of thread on this forum, but I did'nt found any solution.

This is the code I used to load the image:

imm=QImage(53,48,QImage::Format_ARGB32_Premultiplied);
immGL=QImage(53,48,QImage::Format_ARGB32_Premultiplied);
 
imm.load("image.png", "PNG");
immGL = QGLWidget::convertToGLFormat(imm);

imm=QImage(53,48,QImage::Format_ARGB32_Premultiplied);
immGL=QImage(53,48,QImage::Format_ARGB32_Premultiplied);

imm.load("image.png", "PNG");
immGL = QGLWidget::convertToGLFormat(imm);

To copy to clipboard, switch view to plain text mode 

This is the code to draw the image:

glRasterPos2i(x0,y0);
glDrawPixels(w, h, GL_RGBA, GL_UNSIGNED_BYTE, immGL.bits());

glRasterPos2i(x0,y0);
glDrawPixels(w, h, GL_RGBA, GL_UNSIGNED_BYTE, immGL.bits());

To copy to clipboard, switch view to plain text mode 

As a result, the image is drawn with all pixel that should be transparent converted to black.

Any solutions?

Thanks in advance,
Rebe

[wysota]

This is not the fault of QImage but rather of the way you use it. Either your image.png doesn't contain transparency or information about it is lost in OpenGL. And first two lines of your first code snippet can be discarded as lines #4 and #5 respectively will overwrite the objects created earlier.

[Rebe]

Ok, thanks.
I will check OpenGL options.

[GortiZ]

Hi, I've the same issue, did you solved it?
What did you did?

Thanks,
GortiZ

[testqt]

hi i am very new to QT please help me on Immage reading(raw immage) from QT using QgraphisScreen as base calss and derived method from QGLWidget ... if provide me sample code or URL Thanks in advance ....

[wysota]

QImage img("path/to/image");

QImage img("path/to/image");

To copy to clipboard, switch view to plain text mode