Question

The QPNGImagePacker class creates well-compressed PNG animations. More...

#include <qpngio.h>

List of all member functions.

Public Members

• QPNGImagePacker ( QIODevice*iod, intstorage_depth, intconversionflags )
• void setPixelAlignment ( intx )
• bool packImage ( constQImage&img )

---

Detailed Description

The QPNGImagePacker class creates well-compressed PNG animations.

By using transparency, QPNGImagePacker allows you to build a PNG image from a sequence of QImages.

Images are added using packImage().

See also Graphics Classes and Image Processing Classes.

---

Member Function Documentation

QPNGImagePacker::QPNGImagePacker ( QIODevice*iod, intstorage_depth, intconversionflags )

Creates an image packer that writes PNG data to IO device iod using a storage_depth bit encoding (use 8 or 32, depending on the desired quality and compression requirements).

If the image needs to be modified to fit in a lower-resolution result (e.g. converting from 32-bit to 8-bit), use the conversionflags to specify how you'd prefer this to happen.

See also Qt::ImageConversionFlags.

bool QPNGImagePacker::packImage ( constQImage&img )

Adds the image img to the PNG animation, analyzing the differences between this and the previous image to improve compression.

void QPNGImagePacker::setPixelAlignment ( intx )

Aligns pixel differences to x pixels. For example, using 8 can improve playback on certain hardware. Normally the default of 1-pixel alignment (i.e. no alignment) gives better compression and performance.