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The QColor class provides colors based on RGB or HSV values. Más...
#include <qcolor.h>
Tipos públicos | |
enum | Spec { Rgb, Hsv, Rgb, Hsv } |
enum | { Dirt = 0x44495254, Invalid = 0x49000000 } |
enum | Spec { Rgb, Hsv, Rgb, Hsv } |
enum | { Dirt = 0x44495254, Invalid = 0x49000000 } |
Métodos públicos | |
QColor () | |
QColor (int r, int g, int b) | |
QColor (int x, int y, int z, Spec) | |
QColor (QRgb rgb, uint pixel=0xffffffff) | |
QColor (const QString &name) | |
QColor (const char *name) | |
QColor (const QColor &) | |
QColor & | operator= (const QColor &) |
bool | isValid () const |
bool | isDirty () const |
QString | name () const |
void | setNamedColor (const QString &name) |
QRgb | rgb () const |
void | setRgb (int r, int g, int b) |
void | setRgb (QRgb rgb) |
void | getRgb (int *r, int *g, int *b) const |
void | rgb (int *r, int *g, int *b) const |
int | red () const |
int | green () const |
int | blue () const |
void | setHsv (int h, int s, int v) |
void | getHsv (int *h, int *s, int *v) const |
void | hsv (int *h, int *s, int *v) const |
void | getHsv (int &h, int &s, int &v) const |
QColor | light (int f=150) const |
QColor | dark (int f=200) const |
bool | operator== (const QColor &c) const |
bool | operator!= (const QColor &c) const |
uint | alloc () |
uint | pixel () const |
QColor () | |
QColor (int r, int g, int b) | |
QColor (int x, int y, int z, Spec) | |
QColor (QRgb rgb, uint pixel=0xffffffff) | |
QColor (const QString &name) | |
QColor (const char *name) | |
QColor (const QColor &) | |
QColor & | operator= (const QColor &) |
bool | isValid () const |
bool | isDirty () const |
QString | name () const |
void | setNamedColor (const QString &name) |
QRgb | rgb () const |
void | setRgb (int r, int g, int b) |
void | setRgb (QRgb rgb) |
void | getRgb (int *r, int *g, int *b) const |
void | rgb (int *r, int *g, int *b) const |
int | red () const |
int | green () const |
int | blue () const |
void | setHsv (int h, int s, int v) |
void | getHsv (int *h, int *s, int *v) const |
void | hsv (int *h, int *s, int *v) const |
void | getHsv (int &h, int &s, int &v) const |
QColor | light (int f=150) const |
QColor | dark (int f=200) const |
bool | operator== (const QColor &c) const |
bool | operator!= (const QColor &c) const |
uint | alloc () |
uint | pixel () const |
Métodos públicos estáticos | |
static int | maxColors () |
static int | numBitPlanes () |
static int | enterAllocContext () |
static void | leaveAllocContext () |
static int | currentAllocContext () |
static void | destroyAllocContext (int) |
static void | initialize () |
static void | cleanup () |
static QStringList | colorNames () |
static int | maxColors () |
static int | numBitPlanes () |
static int | enterAllocContext () |
static void | leaveAllocContext () |
static int | currentAllocContext () |
static void | destroyAllocContext (int) |
static void | initialize () |
static void | cleanup () |
static QStringList | colorNames () |
Funciones relacionadas | |
(Observar que estas no son funciones miembro.) | |
QDataStream & | operator<< (QDataStream &s, const QColor &c) |
QDataStream & | operator>> (QDataStream &s, QColor &c) |
int | qRed (QRgb rgb) |
int | qGreen (QRgb rgb) |
int | qBlue (QRgb rgb) |
int | qAlpha (QRgb rgba) |
QRgb | qRgb (int r, int g, int b) |
QRgb | qRgba (int r, int g, int b, int a) |
int | qGray (int r, int g, int b) |
int | qGray |
The QColor class provides colors based on RGB or HSV values.
A color is normally specified in terms of RGB (red, green and blue) components, but it is also possible to specify HSV (hue, saturation and value) or set a color name (the names are copied from from the X11 color database).
In addition to the RGB value, a QColor also has a pixel value and a validity. The pixel value is used by the underlying window system to refer to a color. It can be thought of as an index into the display hardware's color table.
The validity (isValid()) indicates whether the color is legal at all. For example, a RGB color with RGB values out of range is illegal. For performance reasons, QColor mostly disregards illegal colors. The result of using an invalid color is unspecified and will usually be surprising.
There are 19 predefined QColor objects: white
, black
, red
, darkRed
, green
, darkGreen
, blue
, darkBlue
, cyan
, darkCyan
, magenta
, darkMagenta
, yellow
, darkYellow
, gray
, darkGray
, lightGray
, color0
and color1
, accessible as members of the Qt namespace (ie. Qt::red
).
qt-colors.png Qt Colors
The colors color0
(zero pixel value) and color1
(non-zero pixel value) are special colors for drawing in bitmaps. Painting with color0
sets the bitmap bits to 0 (transparent, i.e. background), and painting with color1
sets the bits to 1 (opaque, i.e. foreground).
The QColor class has an efficient, dynamic color allocation strategy. A color is normally allocated the first time it is used (lazy allocation), that is, whenever the pixel() function is called. The following steps are taken to allocate a color. If, at any point, a suitable color is found then the appropriate pixel value is returned and the subsequent steps are not taken:
1 Is the pixel value valid? If it is, just return it; otherwise, allocate a pixel value. Check an internal hash table to see if we allocated an equal RGB value earlier. If we did, set the corresponding pixel value for the color and return it. Try to allocate the RGB value. If we succeed, we get a pixel value that we save in the internal table with the RGB value. Return the pixel value. The color could not be allocated. Find the closest matching color, save it in the internal table, and return it.
A color can be set by passing setNamedColor() an RGB string like "#112233", or a color name, e.g. "blue". The names are taken from X11's rgb.txt database but can also be used under Windows. To get a lighter or darker color use light() and dark() respectively. Colors can also be set using setRgb() and setHsv(). The color components can be accessed in one go with rgb() and hsv(), or individually with red(), green() and blue().
Use maxColors() and numBitPlanes() to determine the maximum number of colors and the number of bit planes supported by the underlying window system,
If you need to allocate many colors temporarily, for example in an image viewer application, enterAllocContext(), leaveAllocContext() and destroyAllocContext() will prove useful.
enum QColor::Spec |
enum QColor::Spec |
QColor::QColor | ( | ) | [inline] |
Constructs an invalid color with the RGB value (0, 0, 0). An invalid color is a color that is not properly set up for the underlying window system.
The alpha value of an invalid color is unspecified.
Constructs a color with the RGB or HSV value x, y, z.
The arguments are an RGB value if colorSpec is QColor::Rgb. x (red), y (green), and z (blue). All of them must be in the range 0-255.
The arguments are an HSV value if colorSpec is QColor::Hsv. x (hue) must be -1 for achromatic colors and 0-359 for chromatic colors; y (saturation) and z (value) must both be in the range 0-255.
Constructs a color with the RGB value rgb and a custom pixel value pixel.
If pixel == 0xffffffff (the default), then the color uses the RGB value in a standard way. If pixel is something else, then the pixel value is set directly to pixel, skipping the normal allocation procedure.
QColor::QColor | ( | const QString & | name | ) |
Constructs a named color in the same way as setNamedColor() using name name.
The color is left invalid if name cannot be parsed.
QColor::QColor | ( | const char * | name | ) |
Constructs a named color in the same way as setNamedColor() using name name.
The color is left invalid if name cannot be parsed.
QColor::QColor | ( | const QColor & | c | ) |
Constructs a color that is a copy of c.
QColor::QColor | ( | ) |
QColor::QColor | ( | const QString & | name | ) |
QColor::QColor | ( | const char * | name | ) |
QColor::QColor | ( | const QColor & | ) |
uint QColor::alloc | ( | ) |
Allocates the RGB color and returns the pixel value.
Allocating a color means to obtain a pixel value from the RGB specification. The pixel value is an index into the global color table, but should be considered an arbitrary platform-dependent value.
The pixel() function calls alloc() if necessary, so in general you don't need to call this function.
Allocates the RGB color and returns the pixel value.
Allocating a color means to obtain a pixel value from the RGB specification. The pixel value is an index into the global color table, but should be considered an arbitrary platform-dependent value.
The pixel() function calls alloc() if necessary, so in general you don't need to call this function.
uint QColor::alloc | ( | ) |
int QColor::blue | ( | ) | const [inline] |
Returns the B (blue) component of the RGB value.
int QColor::blue | ( | ) | const |
void QColor::cleanup | ( | ) | [static] |
Internal clean up required for QColor. This function is called from the QApplication destructor.
static void QColor::cleanup | ( | ) | [static] |
QStringList QColor::colorNames | ( | ) | [static] |
Returns a QStringList containing the color names Qt knows about.
static QStringList QColor::colorNames | ( | ) | [static] |
int QColor::currentAllocContext | ( | ) | [static] |
Returns the current color allocation context.
The default context is 0.
static int QColor::currentAllocContext | ( | ) | [static] |
Returns a darker (or lighter) color, but does not change this object.
Returns a darker color if factor is greater than 100. Setting factor to 300 returns a color that has one-third the brightness.
Returns a lighter color if factor is less than 100. We recommend using lighter() for this purpose. If factor is 0 or negative, the return value is unspecified.
(This function converts the current RGB color to HSV, divides V by factor and converts back to RGB.)
void QColor::destroyAllocContext | ( | int | context | ) | [static] |
Destroys a color allocation context, context.
This function deallocates all colors that were allocated in the specified context. If context == -1, it frees up all colors that the application has allocated. If context == -2, it frees up all colors that the application has allocated, except those in the default context.
The function does nothing for true color displays.
static void QColor::destroyAllocContext | ( | int | ) | [static] |
int QColor::enterAllocContext | ( | ) | [static] |
Enters a color allocation context and returns a nonzero unique identifier.
Color allocation contexts are useful for programs that need to allocate many colors and throw them away later, like image viewers. The allocation context functions work for true color displays as well as colormap display, except that QColor::destroyAllocContext() does nothing for true color.
Example:
QPixmap loadPixmap( QString fileName ) { static int alloc_context = 0; if ( alloc_context ) QColor::destroyAllocContext( alloc_context ); alloc_context = QColor::enterAllocContext(); QPixmap pm( fileName ); QColor::leaveAllocContext(); return pm; }
The example code loads a pixmap from file. It frees up all colors that were allocated the last time loadPixmap() was called.
The initial/default context is 0. Qt keeps a list of colors associated with their allocation contexts. You can call destroyAllocContext() to get rid of all colors that were allocated in a specific context.
Calling enterAllocContext() enters an allocation context. The allocation context lasts until you call leaveAllocContext(). QColor has an internal stack of allocation contexts. Each call to enterAllocContex() must have a corresponding leaveAllocContext().
// context 0 active int c1 = QColor::enterAllocContext(); // enter context c1 // context c1 active int c2 = QColor::enterAllocContext(); // enter context c2 // context c2 active QColor::leaveAllocContext(); // leave context c2 // context c1 active QColor::leaveAllocContext(); // leave context c1 // context 0 active // Now, free all colors that were allocated in context c2 QColor::destroyAllocContext( c2 );
You may also want to set the application's color specification. See QApplication::setColorSpec() for more information.
Enters a color allocation context and returns a non-zero unique identifier.
Color allocation contexts are useful for programs that need to allocate many colors and throw them away later, like image viewers. The allocation context functions work for true color displays as well as for colormap displays, except that QColor::destroyAllocContext() does nothing for true color.
Example:
QPixmap loadPixmap( QString fileName ) { static int alloc_context = 0; if ( alloc_context ) QColor::destroyAllocContext( alloc_context ); alloc_context = QColor::enterAllocContext(); QPixmap pm( fileName ); QColor::leaveAllocContext(); return pm; }
The example code loads a pixmap from file. It frees up all colors that were allocated the last time loadPixmap() was called.
The initial/default context is 0. Qt keeps a list of colors associated with their allocation contexts. You can call destroyAllocContext() to get rid of all colors that were allocated in a specific context.
Calling enterAllocContext() enters an allocation context. The allocation context lasts until you call leaveAllocContext(). QColor has an internal stack of allocation contexts. Each call to enterAllocContex() must have a corresponding leaveAllocContext().
// context 0 active int c1 = QColor::enterAllocContext(); // enter context c1 // context c1 active int c2 = QColor::enterAllocContext(); // enter context c2 // context c2 active QColor::leaveAllocContext(); // leave context c2 // context c1 active QColor::leaveAllocContext(); // leave context c1 // context 0 active // Now, free all colors that were allocated in context c2 QColor::destroyAllocContext( c2 );
You may also want to set the application's color specification. See QApplication::setColorSpec() for more information.
static int QColor::enterAllocContext | ( | ) | [static] |
Returns the current RGB value as HSV. The contents of the h, s and v pointers are set to the HSV values. If any of the three pointers are null, the function does nothing.
The hue (which h points to) is set to -1 if the color is achromatic.
int QColor::green | ( | ) | const |
int QColor::green | ( | ) | const [inline] |
Returns the G (green) component of the RGB value.
static void QColor::initialize | ( | ) | [static] |
void QColor::initialize | ( | ) | [static] |
Internal initialization required for QColor. This function is called from the QApplication constructor.
bool QColor::isDirty | ( | ) | const |
bool QColor::isDirty | ( | ) | const |
bool QColor::isValid | ( | ) | const |
bool QColor::isValid | ( | void | ) | const [inline] |
Returns FALSE if the color is invalid, i.e. it was constructed using the default constructor; otherwise returns TRUE.
static void QColor::leaveAllocContext | ( | ) | [static] |
void QColor::leaveAllocContext | ( | ) | [static] |
Leaves a color allocation context.
See enterAllocContext() for a detailed explanation.
Returns a lighter (or darker) color, but does not change this object.
Returns a lighter color if factor is greater than 100. Setting factor to 150 returns a color that is 50% brighter.
Returns a darker color if factor is less than 100. We recommend using dark() for this purpose. If factor is 0 or negative, the return value is unspecified.
(This function converts the current RGB color to HSV, multiplies V by factor, and converts the result back to RGB.)
int QColor::maxColors | ( | ) | [static] |
Returns the maximum number of colors supported by the underlying window system.
Returns the maximum number of colors supported by the underlying window system if the window system uses a palette.
Otherwise returns -1. Use numBitPlanes() to calculate the available colors in that case.
static int QColor::maxColors | ( | ) | [static] |
QString QColor::name | ( | ) | const |
Returns the name of the color in the format "#RRGGBB", i.e. a "#" character followed by three two-digit hexadecimal numbers.
QString QColor::name | ( | ) | const |
int QColor::numBitPlanes | ( | ) | [static] |
Returns the number of color bit planes for the underlying window system.
The returned values is equal to the default pixmap depth;
Returns the number of color bit planes for the underlying window system.
The returned value is equal to the default pixmap depth.
static int QColor::numBitPlanes | ( | ) | [static] |
Returns TRUE if this color has a different RGB value from c; otherwise returns FALSE.
Assigns a copy of the color c and returns a reference to this color.
Returns TRUE if this color has the same RGB value as c; otherwise returns FALSE.
uint QColor::pixel | ( | ) | const |
uint QColor::pixel | ( | ) | const |
Returns the pixel value.
This value is used by the underlying window system to refer to a color. It can be thought of as an index into the display hardware's color table, but the value is an arbitrary 32-bit value.
int QColor::red | ( | ) | const |
int QColor::red | ( | ) | const [inline] |
Returns the R (red) component of the RGB value.
QRgb QColor::rgb | ( | ) | const [inline] |
QRgb QColor::rgb | ( | ) | const |
Sets a HSV color value. h is the hue, s is the saturation and v is the value of the HSV color.
If s or v are not in the range 0-255, or h is < -1, the color is not changed.
void QColor::setNamedColor | ( | const QString & | name | ) |
Sets the RGB value to name, which may be in one of these formats: #RGB (each of R, G and B is a single hex digit) #RRGGBB #RRRGGGBBB #RRRRGGGGBBBB A name from the X color database (rgb.txt) (e.g. "steelblue" or "gainsboro"). These color names also work under Windows.
The color is invalid if name cannot be parsed.
void QColor::setNamedColor | ( | const QString & | name | ) |
void QColor::setRgb | ( | QRgb | rgb | ) |
void QColor::setRgb | ( | QRgb | rgb | ) |
QDataStream & operator<< | ( | QDataStream & | s, |
const QColor & | c | ||
) | [related] |
Writes a color object, c to the stream, s.
QDataStream & operator>> | ( | QDataStream & | s, |
QColor & | c | ||
) | [related] |
Reads a color object, c, from the stream, s.
Returns the blue component of the RGB triplet rgb.
Returns a gray value 0..255 from the (r, g, b) triplet.
The gray value is calculated using the formula (r*11 + g*16 + b*5)/32.
int qGray [related] |
Returns a gray value 0..255 from the given rgb colour.
Returns the green component of the RGB triplet rgb.
Returns the red component of the RGB triplet rgb.
struct { ... } ::D32 QColor::d32 |
struct { ... } ::D8 QColor::d8 |