QCPainter Class

QRectF rect(50, 50, 120, 60);
QRectF shadowRect = rect.translated(2, 4);
// Paint shadow
QCBoxShadow shadow(shadowRect, 30, 15, "#60373F26");
painter.drawBoxShadow(shadow);
// Paint rounded rect
painter.beginPath();
painter.roundRect(rect, 30);
painter.setFillStyle("#DBEB00");
painter.fill();
// Paint text
painter.setTextAlign(QCPainter::TextAlign::Center);
painter.setTextBaseline(QCPainter::TextBaseline::Middle);
QFont font("Titillium Web", 18);
painter.setFont(font);
painter.setFillStyle("#373F26");
painter.fillText("HELLO!", rect);

Member Function Documentation

QCPainter::QCPainter(QObject *parent = nullptr)

Constructs a painter with parent.

[virtual noexcept] QCPainter::~QCPainter()

Destroys the painter.

QCImage QCPainter::addImage(const QImage &image, QCPainter::ImageFlags flags = {})

Adds image with flags available for the painter as a texture. Returns QCImage with the texture id and other information about the image. Returned QCImage can then be used with drawImage and QCImagePattern. After calling this method, image QImage does not need be kept in memory.

Calling with the same image is a cheap operation, since a cache hit is expected.

Care must be taken when optimizing to call addImage() only once. That is not always sufficient, depending on the application design. For example, if the underlying graphics resources are lost, e.g. because the painter is associated with a new QRhi under the hood due to moving a widget to a new top-level, then calling this function is essential in order to re-create the native graphics textures from image.

See also removeImage.

QCImage QCPainter::addImage(QRhiTexture *texture, QCPainter::ImageFlags flags = {})

Adds texture with flags available for the painter as a texture. The flag NativeTexture is set implicitly. The returned QCImage can be used with drawImage and QCImagePattern.

See also removeImage.

QCImage QCPainter::addImage(const QCOffscreenCanvas &canvas, QCPainter::ImageFlags flags = {})

Registers canvas with flags to the painter so that it is available as an image. The returned QCImage can be used with drawImage and QCImagePattern.

See also removeImage.

void QCPainter::arc(float centerX, float centerY, float radius, float a0, float a1, QCPainter::PathWinding direction = PathWinding::ClockWise, bool isConnected = true)

Creates new circle arc shaped sub-path. The arc center is at centerX, centerY, with radius, and the arc is drawn from angle a0 to a1, and swept in direction (ClockWise or CounterClockWise). When isConnected is set to false, arc does not add line from the previous path position to the start of the arc. Angles are specified in radians.

void QCPainter::arc(QPointF centerPoint, float radius, float a0, float a1, QCPainter::PathWinding direction = PathWinding::ClockWise, bool isConnected = true)

Creates new circle arc shaped sub-path. The arc center is at centerPoint, with radius, and the arc is drawn from angle a0 to a1, and swept in direction (ClockWise or CounterClockWise). When isConnected is set to false, arc does not add line from the previous path position to the start of the arc. Angles are specified in radians.

void QCPainter::arcTo(float x1, float y1, float x2, float y2, float radius)

Adds an arc segment at the corner defined by the last path point, and two specified points (x1, y1 and x2, y2) with radius.

void QCPainter::arcTo(QPointF controlPoint1, QPointF controlPoint2, float radius)

Adds an arc segment at the corner defined by the last path point, and two specified points (controlPoint1 and controlPoint2) with radius.

void QCPainter::beginHoleSubPath()

Start a hole subpath. This is equivalent to setPathWinding(QCPainter::PathWinding::ClockWise))

void QCPainter::beginPath()

Begins drawing a new path while clearing the current path.

void QCPainter::beginSolidSubPath()

Start a solid subpath. This is equivalent to setPathWinding(QCPainter::PathWinding::CounterClockWise))

void QCPainter::bezierCurveTo(float cp1X, float cp1Y, float cp2X, float cp2Y, float x, float y)

Adds cubic bezier segment from last point in the path via two control points (cp1X, cp1Y and cp2X, cp2Y) to the specified point (x, y).

void QCPainter::bezierCurveTo(QPointF controlPoint1, QPointF controlPoint2, QPointF endPoint)

Adds cubic bezier segment from last point in the path via two control points (controlPoint1 and controlPoint2) to the specified point endPoint.

qsizetype QCPainter::cacheMemoryUsage() const

Returns the memory usage of texture images in kilobytes.

qsizetype QCPainter::cacheTextureAmount() const

Returns the amount of images in the cache.

void QCPainter::circle(float centerX, float centerY, float radius)

Creates new circle shaped sub-path into ( centerX, centerY) with radius.

void QCPainter::circle(QPointF centerPoint, float radius)

Creates new circle shaped sub-path into centerPoint with radius.

void QCPainter::cleanupResources()

Removes all temporary textures from the cache.

void QCPainter::closePath()

Closes the current sub-path with a line segment. This is equivalent to lineTo([starting point]) as the last path element.

float QCPainter::devicePixelRatio() const

Returns the ratio between physical pixels and device-independent pixels. The default value is 1.0.

void QCPainter::drawBoxShadow(const QCBoxShadow &shadow)

Draws a box shadow. The shadow will be painted with the position, size, color, blur etc. set in the shadow.

See also QCBoxShadow.

void QCPainter::drawImage(const QCImage &image, float x, float y)

Draw image into x, y, at its default size.

void QCPainter::drawImage(const QCImage &image, const QRectF &destinationRect)

Draw image into position and size of destinationRect.

void QCPainter::drawImage(const QCImage &image, const QRectF &sourceRect, const QRectF &destinationRect)

Draw image into position and size of destinationRect, from sourceRect area of image.

void QCPainter::drawImage(const QCImage &image, float x, float y, float width, float height)

Draw image into x, y, at given width and height.

void QCPainter::ellipse(float centerX, float centerY, float radiusX, float radiusY)

Creates new ellipse shaped sub-path into ( centerX, centerY) with radiusX and radiusY.

void QCPainter::ellipse(const QRectF &rect)

Creates new ellipse shaped sub-path into rect. This ellipse will cover the rect area.

void QCPainter::ellipse(QPointF centerPoint, float radiusX, float radiusY)

Creates new ellipse shaped sub-path into centerPoint with radiusX and radiusY.

void QCPainter::fill()

Fills the current path with current fill style.

See also setFillStyle().

void QCPainter::fill(const QCPainterPath &path, int pathGroup = 0, const QTransform &transform = QTransform())

Fills the path with current fill style and belonging into pathGroup. By default, pathGroup is 0, so using the first group. When pathGroup is -1, the path will not be cached on GPU side. More information about using path cache group in {TODO: LINK}. Transform transform is used when filling the path. This does not require calling beginPath().

See also setFillStyle().

void QCPainter::fillRect(float x, float y, float width, float height)

Draws a filled rectangle into specified position ( x, y) at size width, height.

void QCPainter::fillRect(const QRectF &rect)

Draws a filled rectangle into rect. This is an overloaded method using QRectF.

void QCPainter::fillText(const QString &text, float x, float y, float maxWidth = -1, int cacheIndex = -1)

Draws text string at specified location ( x, y), with current textAlign and textBaseline. To make the text wrap into multiple lines, set optional maxWidth parameter to preferred row width in pixels. White space is stripped at the beginning of the rows, the text is split at word boundaries or when new-line characters are encountered. Words longer than the max width are split at nearest character (i.e. no hyphenation).

cacheIndex is optional.

void QCPainter::fillText(const QString &text, const QRectF &rect, int cacheIndex = -1)

Draws text string inside rect, with current textAlign and textBaseline. Width of the rect parameter is used as maxWidth.

This is an overloaded method using QRectF. It is often useful to set the text baseline to TextBaseline::Top or TextBaseline::Middle when painting text with this method.

cacheIndex is optional.

void QCPainter::fillText(const QString &text, QPointF point, float maxWidth = -1, int cacheIndex = -1)

Draws text string at specified point, with current textAlign and textBaseline. To make the text wrap into multiple lines, set optional maxWidth parameter to preferred row width in pixels. White space is stripped at the beginning of the rows, the text is split at word boundaries or when new-line characters are encountered. Words longer than the max width are split at nearest character (i.e. no hyphenation).

This is an overloaded method using QPointF.

const QTransform QCPainter::getTransform() const

Returns the current transform.

void QCPainter::lineTo(float x, float y)

Adds line segment from the last point in the path to the ( x, y) point.

void QCPainter::lineTo(QPointF point)

Adds line segment from the last point in the path to the point.

[static] float QCPainter::mmToPx(float mm)

Static helper method to convert millimeters mm into pixels. This allows doing resolution independent drawing. For example to set the line width to 2mm use:

painter->setLineWidth(QCPainter::mmToPx(2));

void QCPainter::moveTo(float x, float y)

Starts new sub-path with ( x, y) as first point.

void QCPainter::moveTo(QPointF point)

Starts new sub-path with point as first point.

void QCPainter::path(const QPainterPath &path)

Adds path into the current path.

[static] float QCPainter::ptToPx(float pt)

Static helper method to convert points pt into pixels.

void QCPainter::quadraticCurveTo(float cpX, float cpY, float x, float y)

Adds quadratic bezier segment from last point in the path via a control point (cpX, cpY) to the specified point (x, y).

void QCPainter::quadraticCurveTo(QPointF controlPoint, QPointF endPoint)

Adds quadratic bezier segment from last point in the path via a controlPoint to the specified endPoint.

void QCPainter::rect(float x, float y, float width, float height)

Creates new rectangle shaped sub-path in position x, y with size width, height.

void QCPainter::rect(const QRectF &rect)

Creates new rectangle shaped sub-path at rect. This is an overloaded method using QRectF.

void QCPainter::removeImage(int imageId)

Removes image with imageId from the painter.

See also addImage.

void QCPainter::removePathGroup(int pathGroup)

Removes pathGroup from the painter cache. Calling fill() or stroke() for pathGroup after this, will regenerate the path into the group cache.

See also fill() and stroke().

QCPainter::RenderHints QCPainter::renderHints() const

Returns a flag that specifies the rendering hints that are set for this painter.

See also setRenderHints() and setRenderHint().

void QCPainter::reset()

Resets the current painter state to default values.

See also save() and restore().

void QCPainter::resetClipping()

Resets and disables clipping.

See also setClipRect().

void QCPainter::resetTransform()

Resets current transform to a identity matrix.

void QCPainter::restore()

Pops and restores current render state. So previously saved state will be restored. If save() has not been called and the state stack is empty, calling this does nothing.

See also save().

void QCPainter::rotate(float angle)

Rotates current coordinate system by angle. Angle is specified in radians.

void QCPainter::roundRect(float x, float y, float width, float height, float radius)

Creates new rounded rectangle shaped sub-path in position x, y with size width, height. Corners rounding will be radius.

void QCPainter::roundRect(const QRectF &rect, float radius)

Creates new rounded rectangle shaped sub-path at rect with radius corners. This is an overloaded method using QRectF.

void QCPainter::roundRect(const QRectF &rect, float radiusTopLeft, float radiusTopRight, float radiusBottomRight, float radiusBottomLeft)

Creates new rounded rectangle shaped sub-path at rect. Corners rounding can be varying per-corner, with radiusTopLeft, radiusTopRight, radiusBottomRight, radiusBottomLeft.

void QCPainter::roundRect(float x, float y, float width, float height, float radiusTopLeft, float radiusTopRight, float radiusBottomRight, float radiusBottomLeft)

Creates new rounded rectangle shaped sub-path in position x, y with size width, height. Corners rounding can be varying per-corner, with radiusTopLeft, radiusTopRight, radiusBottomRight, radiusBottomLeft.

void QCPainter::save()

Pushes and saves the current render state into a state stack. A matching restore() must be used to restore the state.

See also restore().

void QCPainter::scale(float scale)

Scales the current coordinat system by scale. Both x and y coordinates are scaled evenly.

void QCPainter::scale(float scaleX, float scaleY)

Scales the current coordinat system by scaleX and scaleY.

void QCPainter::setAntialias(float antialias)

Set the current antialiasing amount to antialias in pixels. More antialias means smoother painting. This only affects fill and stroke painting, not images or texts. The default value is 1.0.

Antialiasing can be modified per-path so it can be set before each stroke/fill. To disable antialiasing from the whole QQuickCPainterItem, use QCPainter::RenderHint::Antialiasing render hint.

See also setRenderHints().

void QCPainter::setClipRect(float x, float y, float width, float height)

Sets the current scissor rectangle to (x, y, width, height). The scissor rectangle is transformed by the current transform.

See also resetClipping().

void QCPainter::setClipRect(const QRectF &rect)

Sets the current scissor rectangle to rect. The scissor rectangle is transformed by the current transform.

See also resetClipping().

void QCPainter::setFillStyle(const QColor &color)

Sets the fill style to a solid color. The default fill style is solid black color (0, 0, 0, 1).

void QCPainter::setFillStyle(const QCBrush &brush)

Sets the fill style to brush. The default fill style is solid black color (0, 0, 0, 1).

void QCPainter::setFont(const QFont &font)

Sets the font as currently active font.

void QCPainter::setGlobalAlpha(float alpha)

Sets the global alpha (transparency) value to alpha. This alpha value is applied to all rendered shapes. Already transparent paths will get proportionally more transparent as well. Alpha should be between 0.0 (fully transparent) and 1.0 (fully opaque). By default alpha is 1.0.

void QCPainter::setGlobalBrightness(float value)

Sets the global brightness to value. This brightess is applied to all rendered shapes. A value of 0 will cause painting to be completely black. Value can also be bigger than 1.0, to increase the brightness. By default, brightness is 1.0.

void QCPainter::setGlobalCompositeOperation(QCPainter::CompositeOperation operation)

Sets the global composite operation mode to operation. This mode is applied to all painting operations. The default mode is QCPainter::CompositeOperation::SourceOver.

void QCPainter::setGlobalContrast(float value)

Sets the global contrast to value. This contrast is applied to all rendered shapes. A value of 0 will cause painting to be completely gray (0.5, 0.5, 0.5). Value can also be bigger than 1.0, to increase the contrast. By default, contrast is 1.0.

void QCPainter::setGlobalSaturate(float value)

Sets the global saturations to value. This saturations is applied to all rendered shapes. A value of 0 will disable saturation and cause painting to be completely grayscale. Value can also be bigger than 1.0, to increase the saturation. By default, saturation is 1.0.

void QCPainter::setLineCap(QCPainter::LineCap cap)

Sets the end of the line of stoke to cap. The default line cap is QCPainter::LineCap::Butt.

void QCPainter::setLineJoin(QCPainter::LineJoin join)

Sets the line join of stroke to join. The default line join is QCPainter::LineJoin::Miter.

See also setMiterLimit().

void QCPainter::setLineWidth(float width)

Sets the line width of stroke to width in pixels. The default line width is 1.0.

See also stroke().

void QCPainter::setMiterLimit(float limit)

Sets the miter limit to limit. Miter limit controls when a sharp corner is beveled. When the corner length would become longer than this limit, QCPainter::LineJoin::Bevel will be applied between the lines instead. This has only effect with the QCPainter::LineJoin::Miter line join. The default limit is 10.0.

See also setLineJoin().

void QCPainter::setPathWinding(QCPainter::PathWinding winding)

Sets the current sub-path winding to either CounterClockWise (default) or ClockWise. CounterClockWise draws solid subpaths while ClockWise draws holes.

void QCPainter::setRenderHint(QCPainter::RenderHint hint, bool on = true)

Sets the given render hint on the painter if on is true; otherwise clears the render hint.

See also setRenderHints() and renderHints().

void QCPainter::setRenderHints(QCPainter::RenderHints hints, bool on = true)

Sets the given render hints on the painter if on is true; otherwise clears the render hints.

See also setRenderHint() and renderHints().

void QCPainter::setStrokeStyle(const QColor &color)

Sets the stroke style to a solid color. The default stroke style is solid black color (0, 0, 0, 1).

void QCPainter::setStrokeStyle(const QCBrush &brush)

Sets the stroke style to brush. The default stroke style is solid black color (0, 0, 0, 1).

void QCPainter::setTextAlign(QCPainter::TextAlign align)

Sets the horizontal alignment of text to align. The default alignment is QCPainter::TextAlign::Start.

void QCPainter::setTextAntialias(float antialias)

Set the current text antialiasing amount. The value antialias is multiplier to normal antialiasing, meaning that 0.0 disables antialiasing and 2.0 doubles it. The default value is 1.0.

void QCPainter::setTextBaseline(QCPainter::TextBaseline baseline)

Sets the vertical alignment (baseline) of text to baseline. The default alignment is QCPainter::TextBaseline::Alphabetic.

void QCPainter::setTextDirection(QCPainter::TextDirection direction)

Sets the direction (baseline) of text to direction. The default direction is QCPainter::TextDirection::Inherit.

void QCPainter::setTextLineHeight(float height)

Sets the line height adjustment in pixels to height for wrapped text. The default line height is 0.

void QCPainter::setTextWrapMode(QCPainter::WrapMode wrapMode)

Sets the text wrap mode to wrapMode. The default wrap mode is QCPainter::WrapMode::NoWrap.

void QCPainter::setTransform(const QTransform &transform)

Resets the current transform and uses transform instead.

See also transform().

void QCPainter::skew(float angleX, float angleY = 0.0f)

Skews (shears) the current coordinate system along X axis by angleX and along Y axis by angleY. Angles are specifid in radians.

void QCPainter::stroke()

Strokes the current path with current stroke style.

See also setStrokeStyle().

void QCPainter::stroke(const QCPainterPath &path, int pathGroup = 0, const QTransform &transform = QTransform())

Strokes the path with current stroke style and belonging into pathGroup. By default, pathGroup is 0, so using the first group. When pathGroup is -1, the path will not be cached on GPU side. More information about using path cache group in {TODO: LINK}. Transform transform is used when filling the path. This does not require calling beginPath().

See also setStrokeStyle().

void QCPainter::strokeRect(float x, float y, float width, float height)

Draws a stoked rectangle into specified position ( x, y) at size width, height.

void QCPainter::strokeRect(const QRectF &rect)

Draws a stoked rectangle into rect. This is an overloaded method using QRectF.

QRectF QCPainter::textBoundingBox(const QString &text, float x, float y, float maxWidth = -1)

Measures bounding box of a text string at (x, y). To measure multi-line text, set optional maxWidth parameter to preferred row width in pixels. Returns QRectF with values [xmin, ymin, width, height]. Measured values are returned in local coordinate space.

QRectF QCPainter::textBoundingBox(const QString &text, const QRectF &rect)

Measures bounding box of a text string at rect. Returns QRectF with values [xmin, ymin, width, height]. Measured values are returned in local coordinate space.

QRectF QCPainter::textBoundingBox(const QString &text, QPointF point, float maxWidth = -1)

Measures bounding box of a text string at point. To measure multi-line text, set optional maxWidth parameter to preferred row width in pixels. Returns QRectF with values [xmin, ymin, width, height]. Measured values are returned in local coordinate space.

void QCPainter::transform(const QTransform &transform)

Multiplies the current coordinate system by specified transform.

See also setTransform().

void QCPainter::translate(float x, float y)

Translates current coordinate system by x and y.

void QCPainter::translate(QPointF point)

Translates current coordinate system by point.