QPainter Class
The QPainter class performs low-level painting on widgets and other paint devices.
| Header: | #include <QPainter> |
| qmake: | QT += gui |
| Inherited By: |
Public Types
| class | PixmapFragment |
| enum | CompositionMode { CompositionMode_SourceOver, CompositionMode_DestinationOver, CompositionMode_Clear, CompositionMode_Source, CompositionMode_Destination, …, RasterOp_SourceOrNotDestination } |
| enum | PixmapFragmentHint { OpaqueHint } |
| flags | PixmapFragmentHints |
| enum | RenderHint { Antialiasing, TextAntialiasing, SmoothPixmapTransform, HighQualityAntialiasing, NonCosmeticDefaultPen, …, LosslessImageRendering } |
| flags | RenderHints |
Public Functions
Public Functions
| QPainter(QPaintDevice *device) | |
| QPainter() | |
| ~QPainter() | |
| const QBrush & | background() const |
| Qt::BGMode | backgroundMode() const |
| bool | begin(QPaintDevice *device) |
| void | beginNativePainting() |
| QRectF | boundingRect(const QRectF &rectangle, int flags, const QString &text) |
| QRect | boundingRect(const QRect &rectangle, int flags, const QString &text) |
| QRect | boundingRect(int x, int y, int w, int h, int flags, const QString &text) |
| QRectF | boundingRect(const QRectF &rectangle, const QString &text, const QTextOption &option = QTextOption()) |
| const QBrush & | brush() const |
| QPoint | brushOrigin() const |
| QRectF | clipBoundingRect() const |
| QPainterPath | clipPath() const |
| QRegion | clipRegion() const |
| QTransform | combinedTransform() const |
| QPainter::CompositionMode | compositionMode() const |
| QPaintDevice * | device() const |
| const QTransform & | deviceTransform() const |
| void | drawArc(const QRectF &rectangle, int startAngle, int spanAngle) |
| void | drawArc(const QRect &rectangle, int startAngle, int spanAngle) |
| void | drawArc(int x, int y, int width, int height, int startAngle, int spanAngle) |
| void | drawChord(const QRectF &rectangle, int startAngle, int spanAngle) |
| void | drawChord(int x, int y, int width, int height, int startAngle, int spanAngle) |
| void | drawChord(const QRect &rectangle, int startAngle, int spanAngle) |
| void | drawConvexPolygon(const QPointF *points, int pointCount) |
| void | drawConvexPolygon(const QPolygonF &polygon) |
| void | drawConvexPolygon(const QPoint *points, int pointCount) |
| void | drawConvexPolygon(const QPolygon &polygon) |
| void | drawEllipse(const QRectF &rectangle) |
| void | drawEllipse(const QRect &rectangle) |
| void | drawEllipse(int x, int y, int width, int height) |
| void | drawEllipse(const QPointF ¢er, qreal rx, qreal ry) |
| void | drawEllipse(const QPoint ¢er, int rx, int ry) |
| void | drawGlyphRun(const QPointF &position, const QGlyphRun &glyphs) |
| void | drawImage(const QRectF &target, const QImage &image, const QRectF &source, Qt::ImageConversionFlags flags = Qt::AutoColor) |
| void | drawImage(const QRect &target, const QImage &image, const QRect &source, Qt::ImageConversionFlags flags = Qt::AutoColor) |
| void | drawImage(const QPointF &point, const QImage &image, const QRectF &source, Qt::ImageConversionFlags flags = Qt::AutoColor) |
| void | drawImage(const QPoint &point, const QImage &image, const QRect &source, Qt::ImageConversionFlags flags = Qt::AutoColor) |
| void | drawImage(const QRectF &rectangle, const QImage &image) |
| void | drawImage(const QRect &rectangle, const QImage &image) |
| void | drawImage(const QPointF &point, const QImage &image) |
| void | drawImage(const QPoint &point, const QImage &image) |
| void | drawImage(int x, int y, const QImage &image, int sx = 0, int sy = 0, int sw = -1, int sh = -1, Qt::ImageConversionFlags flags = Qt::AutoColor) |
| void | drawLine(const QLineF &line) |
| void | drawLine(const QLine &line) |
| void | drawLine(int x1, int y1, int x2, int y2) |
| void | drawLine(const QPoint &p1, const QPoint &p2) |
| void | drawLine(const QPointF &p1, const QPointF &p2) |
| void | drawLines(const QLineF *lines, int lineCount) |
| void | drawLines(const QVector<QLineF> &lines) |
| void | drawLines(const QPointF *pointPairs, int lineCount) |
| void | drawLines(const QVector<QPointF> &pointPairs) |
| void | drawLines(const QLine *lines, int lineCount) |
| void | drawLines(const QVector<QLine> &lines) |
| void | drawLines(const QPoint *pointPairs, int lineCount) |
| void | drawLines(const QVector<QPoint> &pointPairs) |
| void | drawPath(const QPainterPath &path) |
| void | drawPicture(const QPointF &point, const QPicture &picture) |
| void | drawPicture(int x, int y, const QPicture &picture) |
| void | drawPicture(const QPoint &point, const QPicture &picture) |
| void | drawPie(const QRectF &rectangle, int startAngle, int spanAngle) |
| void | drawPie(int x, int y, int width, int height, int startAngle, int spanAngle) |
| void | drawPie(const QRect &rectangle, int startAngle, int spanAngle) |
| void | drawPixmap(const QRectF &target, const QPixmap &pixmap, const QRectF &source) |
| void | drawPixmap(const QRect &target, const QPixmap &pixmap, const QRect &source) |
| void | drawPixmap(int x, int y, int w, int h, const QPixmap &pixmap, int sx, int sy, int sw, int sh) |
| void | drawPixmap(int x, int y, const QPixmap &pixmap, int sx, int sy, int sw, int sh) |
| void | drawPixmap(const QPointF &point, const QPixmap &pixmap, const QRectF &source) |
| void | drawPixmap(const QPoint &point, const QPixmap &pixmap, const QRect &source) |
| void | drawPixmap(const QPointF &point, const QPixmap &pixmap) |
| void | drawPixmap(const QPoint &point, const QPixmap &pixmap) |
| void | drawPixmap(int x, int y, const QPixmap &pixmap) |
| void | drawPixmap(const QRect &rectangle, const QPixmap &pixmap) |
| void | drawPixmap(int x, int y, int width, int height, const QPixmap &pixmap) |
| void | drawPixmapFragments(const QPainter::PixmapFragment *fragments, int fragmentCount, const QPixmap &pixmap, QPainter::PixmapFragmentHints hints = PixmapFragmentHints()) |
| void | drawPoint(const QPointF &position) |
| void | drawPoint(const QPoint &position) |
| void | drawPoint(int x, int y) |
| void | drawPoints(const QPointF *points, int pointCount) |
| void | drawPoints(const QPolygonF &points) |
| void | drawPoints(const QPoint *points, int pointCount) |
| void | drawPoints(const QPolygon &points) |
| void | drawPolygon(const QPointF *points, int pointCount, Qt::FillRule fillRule = Qt::OddEvenFill) |
| void | drawPolygon(const QPolygonF &points, Qt::FillRule fillRule = Qt::OddEvenFill) |
| void | drawPolygon(const QPoint *points, int pointCount, Qt::FillRule fillRule = Qt::OddEvenFill) |
| void | drawPolygon(const QPolygon &points, Qt::FillRule fillRule = Qt::OddEvenFill) |
| void | drawPolyline(const QPointF *points, int pointCount) |
| void | drawPolyline(const QPolygonF &points) |
| void | drawPolyline(const QPoint *points, int pointCount) |
| void | drawPolyline(const QPolygon &points) |
| void | drawRect(const QRectF &rectangle) |
| void | drawRect(int x, int y, int width, int height) |
| void | drawRect(const QRect &rectangle) |
| void | drawRects(const QRectF *rectangles, int rectCount) |
| void | drawRects(const QVector<QRectF> &rectangles) |
| void | drawRects(const QRect *rectangles, int rectCount) |
| void | drawRects(const QVector<QRect> &rectangles) |
| void | drawRoundedRect(const QRectF &rect, qreal xRadius, qreal yRadius, Qt::SizeMode mode = Qt::AbsoluteSize) |
| void | drawRoundedRect(int x, int y, int w, int h, qreal xRadius, qreal yRadius, Qt::SizeMode mode = Qt::AbsoluteSize) |
| void | drawRoundedRect(const QRect &rect, qreal xRadius, qreal yRadius, Qt::SizeMode mode = Qt::AbsoluteSize) |
| void | drawStaticText(const QPointF &topLeftPosition, const QStaticText &staticText) |
| void | drawStaticText(const QPoint &topLeftPosition, const QStaticText &staticText) |
| void | drawStaticText(int left, int top, const QStaticText &staticText) |
| void | drawText(const QRectF &rectangle, int flags, const QString &text, QRectF *boundingRect = nullptr) |
| void | drawText(const QPointF &position, const QString &text) |
| void | drawText(const QPoint &position, const QString &text) |
| void | drawText(int x, int y, const QString &text) |
| void | drawText(const QRect &rectangle, int flags, const QString &text, QRect *boundingRect = nullptr) |
| void | drawText(int x, int y, int width, int height, int flags, const QString &text, QRect *boundingRect = nullptr) |
| void | drawText(const QRectF &rectangle, const QString &text, const QTextOption &option = QTextOption()) |
| void | drawTiledPixmap(const QRectF &rectangle, const QPixmap &pixmap, const QPointF &position = QPointF()) |
| void | drawTiledPixmap(int x, int y, int width, int height, const QPixmap &pixmap, int sx = 0, int sy = 0) |
| void | drawTiledPixmap(const QRect &rectangle, const QPixmap &pixmap, const QPoint &position = QPoint()) |
| bool | end() |
| void | endNativePainting() |
| void | eraseRect(const QRectF &rectangle) |
| void | eraseRect(int x, int y, int width, int height) |
| void | eraseRect(const QRect &rectangle) |
| void | fillPath(const QPainterPath &path, const QBrush &brush) |
| void | fillRect(const QRectF &rectangle, const QBrush &brush) |
| void | fillRect(int x, int y, int width, int height, const QBrush &brush) |
| void | fillRect(const QRect &rectangle, const QBrush &brush) |
| void | fillRect(const QRectF &rectangle, const QColor &color) |
| void | fillRect(int x, int y, int width, int height, const QColor &color) |
| void | fillRect(const QRect &rectangle, const QColor &color) |
| void | fillRect(int x, int y, int width, int height, Qt::GlobalColor color) |
| void | fillRect(const QRect &rectangle, Qt::GlobalColor color) |
| void | fillRect(const QRectF &rectangle, Qt::GlobalColor color) |
| void | fillRect(int x, int y, int width, int height, Qt::BrushStyle style) |
| void | fillRect(const QRect &rectangle, Qt::BrushStyle style) |
| void | fillRect(const QRectF &rectangle, Qt::BrushStyle style) |
| void | fillRect(int x, int y, int width, int height, QGradient::Preset preset) |
| void | fillRect(const QRect &rectangle, QGradient::Preset preset) |
| void | fillRect(const QRectF &rectangle, QGradient::Preset preset) |
| const QFont & | font() const |
| QFontInfo | fontInfo() const |
| QFontMetrics | fontMetrics() const |
| bool | hasClipping() const |
| bool | isActive() const |
| Qt::LayoutDirection | layoutDirection() const |
| qreal | opacity() const |
| QPaintEngine * | paintEngine() const |
| const QPen & | pen() const |
| QPainter::RenderHints | renderHints() const |
| void | resetTransform() |
| void | restore() |
| void | rotate(qreal angle) |
| void | save() |
| void | scale(qreal sx, qreal sy) |
| void | setBackground(const QBrush &brush) |
| void | setBackgroundMode(Qt::BGMode mode) |
| void | setBrush(const QBrush &brush) |
| void | setBrush(Qt::BrushStyle style) |
| void | setBrushOrigin(const QPointF &position) |
| void | setBrushOrigin(int x, int y) |
| void | setBrushOrigin(const QPoint &position) |
| void | setClipPath(const QPainterPath &path, Qt::ClipOperation operation = Qt::ReplaceClip) |
| void | setClipRect(const QRectF &rectangle, Qt::ClipOperation operation = Qt::ReplaceClip) |
| void | setClipRect(const QRect &rectangle, Qt::ClipOperation operation = Qt::ReplaceClip) |
| void | setClipRect(int x, int y, int width, int height, Qt::ClipOperation operation = Qt::ReplaceClip) |
| void | setClipRegion(const QRegion ®ion, Qt::ClipOperation operation = Qt::ReplaceClip) |
| void | setClipping(bool enable) |
| void | setCompositionMode(QPainter::CompositionMode mode) |
| void | setFont(const QFont &font) |
| void | setLayoutDirection(Qt::LayoutDirection direction) |
| void | setOpacity(qreal opacity) |
| void | setPen(const QPen &pen) |
| void | setPen(const QColor &color) |
| void | setPen(Qt::PenStyle style) |
| void | setRenderHint(QPainter::RenderHint hint, bool on = true) |
| void | setRenderHints(QPainter::RenderHints hints, bool on = true) |
| void | setTransform(const QTransform &transform, bool combine = false) |
| void | setViewTransformEnabled(bool enable) |
| void | setViewport(const QRect &rectangle) |
| void | setViewport(int x, int y, int width, int height) |
| void | setWindow(const QRect &rectangle) |
| void | setWindow(int x, int y, int width, int height) |
| void | setWorldMatrixEnabled(bool enable) |
| void | setWorldTransform(const QTransform &matrix, bool combine = false) |
| void | shear(qreal sh, qreal sv) |
| void | strokePath(const QPainterPath &path, const QPen &pen) |
| bool | testRenderHint(QPainter::RenderHint hint) const |
| const QTransform & | transform() const |
| void | translate(const QPointF &offset) |
| void | translate(const QPoint &offset) |
| void | translate(qreal dx, qreal dy) |
| bool | viewTransformEnabled() const |
| QRect | viewport() const |
| QRect | window() const |
| bool | worldMatrixEnabled() const |
| const QTransform & | worldTransform() const |
Detailed Description
QPainter provides highly optimized functions to do most of the drawing GUI programs require. It can draw everything from simple lines to complex shapes like pies and chords. It can also draw aligned text and pixmaps. Normally, it draws in a "natural" coordinate system, but it can also do view and world transformation. QPainter can operate on any object that inherits the QPaintDevice class.
The common use of QPainter is inside a widget's paint event: Construct and customize (e.g. set the pen or the brush) the painter. Then draw. Remember to destroy the QPainter object after drawing. For example:
void SimpleExampleWidget::paintEvent(QPaintEvent *)
{
QPainter painter(this);
painter.setPen(Qt::blue);
painter.setFont(QFont("Arial", 30));
painter.drawText(rect(), Qt::AlignCenter, "Qt");
}
参考：https://doc.qt.io/qt-5/qpainter.html
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