KPixmap Class Reference

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The KPixmap class is an off-screen buffer paint device that extends the features of QPixmap More...

#include <kpixmap.h>

Inherits: QPixmap (qt)

Public Members


Detailed Description

The KPixmap class is an off-screen buffer paint device that extends the features of QPixmap. KPixmap has two new color modes, WebColor and LowColor, applicable to 8bpp displays.

In WebColor mode all images are dithered to the Netscape palette, even when they have their own color table. WebColor is the default mode for KPixmap so that standard applications can share the Netscape palette across the desktop.

In LowColor mode images are checked to see if their color table matches the KDE icon palette. If the color tables do not match, the images are dithered to a minimal 3x3x3 color cube. LowColor mode can be used to load icons, background images etc. so that components of the desktop which are always present use no more than 40 colors.


KPixmap() [public]

Creates a null pixmap

~KPixmap() [public]

Destroys the pixmap.

void gradientFill( QColor ca, QColor cb, bool upDown = TRUE, int ncols = 3 ) [public]

Fills the pixmap with a color blend running from color ca to color cb.

If upDown is TRUE the blend will run from the top to the bottom of the pixmap. If upDown is FALSE the blend will run from the right to the left of the pixmap.

By default, the blend will use 3 colors on 8 bpp displays, 32 colors on 16 bpp displays and unlimited colors at higher dislay depths. For 8bpp displays ncols specifies an alternative number of colors to use. The greater the number of colors allocated the better the appearance of the gradient but the longer it takes to make.

void patternFill( QColor ca, QColor cb, uint pattern[8] ) [public]

Fills the pixmap with a two color pattern, specified by the pattern bits in pattern[], the color ca to be used for the background and the color cb to be used for the foreground.

bool convertFromImage( const QImage &img, int conversion_flags ) [public]

Converts an image and sets this pixmap. Returns TRUE if successful.

The conversion_flags argument is a bitwise-OR from the following choices. The options marked (default) are the choice if no other choice from the list is included (they are zero):

Color/Mono preference

WebColor - If the image has depth 1 and contains only black and white pixels then the pixmap becomes monochrome. If the pixmap has a depth of 8 bits per pixel then the Netscape palette is used for the pixmap color table. LowColor - If the image has depth 1 and contains only black and white pixels then the pixmap becomes monochrome. If the pixmap has a depth of 8 bits per pixel and the image does not posess a color table that matches the Icon palette a 3x3x3 color cube is used for the pixmap color table. AutoColor (default) - If the image has depth 1 and contains only black and white pixels, then the pixmap becomes monochrome. ColorOnly - The pixmap is dithered/converted to the native display depth. MonoOnly - The pixmap becomes monochrome. If necessary, it is dithered using the chosen dithering algorithm.

Dithering mode preference, for RGB channels

DiffuseDither (default) - a high quality dither OrderedDither - a faster more ordered dither ThresholdDither - no dithering, closest color is used

Dithering mode preference, for alpha channel

DiffuseAlphaDither - a high quality dither OrderedAlphaDither - a faster more ordered dither ThresholdAlphaDither (default) - no dithering

Color matching versus dithering preference

PreferDither - always dither 32-bit images when the image is being converted to 8-bits. This is the default when converting to a pixmap. AvoidDither - only dither 32-bit images if the image has more than 256 colours and it is being converted to 8-bits. This is the default when an image is converted for the purpose of saving to a file.

Passing 0 for conversion_flags gives all the default options.

bool load( const char *fileName, const char *format, int conversion_flags ) [public]

Loads a pixmap from the file fileName. Returns TRUE if successful, or FALSE if the pixmap could not be loaded.

If format is specified, the loader attempts to read the pixmap using the specified format. If format is not specified (default), the loader reads a few bytes from the header to guess the file format.

See the convertFromImage() documentation for a description of the conversion_flags argument.

The QImageIO documentation lists the supported image formats and explains how to add extra formats.


Documentation generated by tasin@cd1 on Die Nov 30 17:31:35 CET 1999
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