Handles rendering text using rich formatting options, including drop shadows, buffers and background shapes. More...

#include <qgstextrenderer.h>

Static Public Member Functions
static Qgis::TextHorizontalAlignment	convertQtHAlignment (Qt::Alignment alignment)
	Converts a Qt horizontal alignment flag to a Qgis::TextHorizontalAlignment value. More...

static Qgis::TextVerticalAlignment	convertQtVAlignment (Qt::Alignment alignment)
	Converts a Qt vertical alignment flag to a Qgis::TextVerticalAlignment value. More...

static void	drawDocument (const QRectF &rect, const QgsTextFormat &format, const QgsTextDocument &document, const QgsTextDocumentMetrics &metrics, QgsRenderContext &context, Qgis::TextHorizontalAlignment horizontalAlignment=Qgis::TextHorizontalAlignment::Left, Qgis::TextVerticalAlignment verticalAlignment=Qgis::TextVerticalAlignment::Top, double rotation=0, Qgis::TextLayoutMode mode=Qgis::TextLayoutMode::Rectangle, Qgis::TextRendererFlags flags=Qgis::TextRendererFlags())
	Draws a text document within a rectangle using the specified settings. More...

static Q_DECL_DEPRECATED void	drawPart (const QRectF &rect, double rotation, Qgis::TextHorizontalAlignment alignment, const QStringList &textLines, QgsRenderContext &context, const QgsTextFormat &format, Qgis::TextComponent part, bool drawAsOutlines=true)
	Draws a single component of rendered text using the specified settings. More...

static Q_DECL_DEPRECATED void	drawPart (QPointF origin, double rotation, Qgis::TextHorizontalAlignment alignment, const QStringList &textLines, QgsRenderContext &context, const QgsTextFormat &format, Qgis::TextComponent part, bool drawAsOutlines=true)
	Draws a single component of rendered text using the specified settings. More...

static void	drawText (const QRectF &rect, double rotation, Qgis::TextHorizontalAlignment alignment, const QStringList &textLines, QgsRenderContext &context, const QgsTextFormat &format, bool drawAsOutlines=true, Qgis::TextVerticalAlignment vAlignment=Qgis::TextVerticalAlignment::Top, Qgis::TextRendererFlags flags=Qgis::TextRendererFlags(), Qgis::TextLayoutMode mode=Qgis::TextLayoutMode::Rectangle)
	Draws text within a rectangle using the specified settings. More...

static void	drawText (QPointF point, double rotation, Qgis::TextHorizontalAlignment alignment, const QStringList &textLines, QgsRenderContext &context, const QgsTextFormat &format, bool drawAsOutlines=true)
	Draws text at a point origin using the specified settings. More...

static QFontMetricsF	fontMetrics (QgsRenderContext &context, const QgsTextFormat &format, double scaleFactor=1.0)
	Returns the font metrics for the given text format, when rendered in the specified render context. More...

static int	sizeToPixel (double size, const QgsRenderContext &c, Qgis::RenderUnit unit, const QgsMapUnitScale &mapUnitScale=QgsMapUnitScale())
	Calculates pixel size (considering output size should be in pixel or map units, scale factors and optionally oversampling) More...

static double	textHeight (const QgsRenderContext &context, const QgsTextFormat &format, const QStringList &textLines, Qgis::TextLayoutMode mode=Qgis::TextLayoutMode::Point, QFontMetricsF *fontMetrics=nullptr, Qgis::TextRendererFlags flags=Qgis::TextRendererFlags(), double maxLineWidth=0)
	Returns the height of a text based on a given format. More...

static double	textHeight (const QgsRenderContext &context, const QgsTextFormat &format, QChar character, bool includeEffects=false)
	Returns the height of a character when rendered with the specified text format. More...

static bool	textRequiresWrapping (const QgsRenderContext &context, const QString &text, double width, const QgsTextFormat &format)
	Returns `true` if the specified text requires line wrapping in order to fit within the specified width (in painter units). More...

static double	textWidth (const QgsRenderContext &context, const QgsTextFormat &format, const QStringList &textLines, QFontMetricsF *fontMetrics=nullptr)
	Returns the width of a text based on a given format. More...

static QStringList	wrappedText (const QgsRenderContext &context, const QString &text, double width, const QgsTextFormat &format)
	Wraps a text string to multiple lines, such that each individual line will fit within the specified width (in painter units). More...

Static Public Attributes
static constexpr double	FONT_WORKAROUND_SCALE = 10
	Scale factor for upscaling font sizes and downscaling destination painter devices. More...

Friends
class	QgsLabelPreview

class	QgsVectorLayerLabelProvider

Detailed Description

Handles rendering text using rich formatting options, including drop shadows, buffers and background shapes.

Since: QGIS 3.0

Definition at line 41 of file qgstextrenderer.h.

Member Function Documentation

◆ convertQtHAlignment()

Qgis::TextHorizontalAlignment QgsTextRenderer::convertQtHAlignment ( Qt::Alignment alignment )

static

Converts a Qt horizontal alignment flag to a Qgis::TextHorizontalAlignment value.

See also: convertQtVAlignment()

Since: QGIS 3.16

Definition at line 47 of file qgstextrenderer.cpp.

◆ convertQtVAlignment()

Qgis::TextVerticalAlignment QgsTextRenderer::convertQtVAlignment ( Qt::Alignment alignment )

static

Converts a Qt vertical alignment flag to a Qgis::TextVerticalAlignment value.

See also: convertQtHAlignment()

Since: QGIS 3.16

Definition at line 62 of file qgstextrenderer.cpp.

◆ drawDocument()

void QgsTextRenderer::drawDocument	(	const QRectF &	rect,
		const QgsTextFormat &	format,
		const QgsTextDocument &	document,
		const QgsTextDocumentMetrics &	metrics,
		QgsRenderContext &	context,
		Qgis::TextHorizontalAlignment	horizontalAlignment = `Qgis::TextHorizontalAlignment::Left`,
		Qgis::TextVerticalAlignment	verticalAlignment = `Qgis::TextVerticalAlignment::Top`,
		double	rotation = `0`,
		Qgis::TextLayoutMode	mode = `Qgis::TextLayoutMode::Rectangle`,
		Qgis::TextRendererFlags	flags = `Qgis::TextRendererFlags()`
	)

static

Draws a text document within a rectangle using the specified settings.

Calling this method is more efficient than calling drawText() if the text document and metrics have already been calculated.

Warning: Unlike drawText(), this method does not automatically update data defined properties in the text format. This is the caller's responsibility to do, and must be done prior to generating the text document and metrics.

Parameters

rect	destination rectangle for text
format	base text format
document	text document to draw
metrics	precalculated text metrics
context	destination render context
horizontalAlignment	horizontal alignment
verticalAlignment	vertical alignment
rotation	text rotation
mode	text layout mode. Only Qgis::TextLayoutMode::Rectangle, Qgis::TextLayoutMode::RectangleCapHeightBased and Qgis::TextLayoutMode::RectangleAscentBased are accepted.
flags	text rendering flags

Since: QGIS 3.30

Definition at line 111 of file qgstextrenderer.cpp.

◆ drawPart() [1/2]

void QgsTextRenderer::drawPart	(	const QRectF &	rect,
		double	rotation,
		Qgis::TextHorizontalAlignment	alignment,
		const QStringList &	textLines,
		QgsRenderContext &	context,
		const QgsTextFormat &	format,
		Qgis::TextComponent	part,
		bool	drawAsOutlines = `true`
	)

static

Draws a single component of rendered text using the specified settings.

Parameters

rect	destination rectangle for text
rotation	text rotation
alignment	horizontal alignment
textLines	list of lines of text to draw
context	render context
format	text format
part	component of text to draw. Note that Shadow parts cannot be drawn individually and instead are drawn with their associated part (e.g., drawn together with the text or background parts)
drawAsOutlines	set to `false` to render text as text. This allows outputs to formats like SVG to maintain text as text objects, but at the cost of degraded rendering and may result in side effects like misaligned text buffers. This setting is deprecated and has no effect as of QGIS 3.4.3 and the text format should be set using QgsRenderContext::setTextRenderFormat() instead.

Deprecated:: Private API only, will be removed in 4.0

Definition at line 174 of file qgstextrenderer.cpp.

◆ drawPart() [2/2]

void QgsTextRenderer::drawPart	(	QPointF	origin,
		double	rotation,
		Qgis::TextHorizontalAlignment	alignment,
		const QStringList &	textLines,
		QgsRenderContext &	context,
		const QgsTextFormat &	format,
		Qgis::TextComponent	part,
		bool	drawAsOutlines = `true`
	)

static

Draws a single component of rendered text using the specified settings.

Parameters

origin	origin for start of text. Y coordinate will be used as baseline.
rotation	text rotation
alignment	horizontal alignment
textLines	list of lines of text to draw
context	render context
format	text format
part	component of text to draw. Note that Shadow parts cannot be drawn individually and instead are drawn with their associated part (e.g., drawn together with the text or background parts)
drawAsOutlines	set to `false` to render text as text. This allows outputs to formats like SVG to maintain text as text objects, but at the cost of degraded rendering and may result in side effects like misaligned text buffers. This setting is deprecated and has no effect as of QGIS 3.4.3 and the text format should be set using QgsRenderContext::setTextRenderFormat() instead.

Deprecated:: Private API only, will be removed in 4.0

Definition at line 257 of file qgstextrenderer.cpp.

◆ drawText() [1/2]

void QgsTextRenderer::drawText	(	const QRectF &	rect,
		double	rotation,
		Qgis::TextHorizontalAlignment	alignment,
		const QStringList &	textLines,
		QgsRenderContext &	context,
		const QgsTextFormat &	format,
		bool	drawAsOutlines = `true`,
		Qgis::TextVerticalAlignment	vAlignment = `Qgis::TextVerticalAlignment::Top`,
		Qgis::TextRendererFlags	flags = `Qgis::TextRendererFlags()`,
		Qgis::TextLayoutMode	mode = `Qgis::TextLayoutMode::Rectangle`
	)

static

Draws text within a rectangle using the specified settings.

Parameters

rect	destination rectangle for text
rotation	text rotation
alignment	horizontal alignment
textLines	list of lines of text to draw
context	render context
format	text format
drawAsOutlines	set to `false` to render text as text. This allows outputs to formats like SVG to maintain text as text objects, but at the cost of degraded rendering and may result in side effects like misaligned text buffers. This setting is deprecated and has no effect as of QGIS 3.4.3 and the text format should be set using QgsRenderContext::setTextRenderFormat() instead.
vAlignment	vertical alignment (since QGIS 3.16)
flags	text rendering flags (since QGIS 3.24)
mode	text layout mode. Only Qgis::TextLayoutMode::Rectangle, Qgis::TextLayoutMode::RectangleCapHeightBased and Qgis::TextLayoutMode::RectangleAscentBased are accepted (since QGIS 3.30)

See also: drawDocument(), which is more efficient if the text document and metrics have already been calculated.

Definition at line 82 of file qgstextrenderer.cpp.

◆ drawText() [2/2]

void QgsTextRenderer::drawText	(	QPointF	point,
		double	rotation,
		Qgis::TextHorizontalAlignment	alignment,
		const QStringList &	textLines,
		QgsRenderContext &	context,
		const QgsTextFormat &	format,
		bool	drawAsOutlines = `true`
	)

static

Draws text at a point origin using the specified settings.

Parameters

point	origin of text
rotation	text rotation
alignment	horizontal alignment
textLines	list of lines of text to draw
context	render context
format	text format
drawAsOutlines	set to `false` to render text as text. This allows outputs to formats like SVG to maintain text as text objects, but at the cost of degraded rendering and may result in side effects like misaligned text buffers. This setting is deprecated and has no effect as of QGIS 3.4.3 and the text format should be set using QgsRenderContext::setTextRenderFormat() instead.

Definition at line 128 of file qgstextrenderer.cpp.

◆ fontMetrics()

QFontMetricsF QgsTextRenderer::fontMetrics	(	QgsRenderContext &	context,
		const QgsTextFormat &	format,
		double	scaleFactor = `1.0`
	)

static

Returns the font metrics for the given text format, when rendered in the specified render context.

The font metrics will take into account all scaling required by the render context.

The optional scaleFactor argument can specify a font size scaling factor. It is recommended to set this to QgsTextRenderer::FONT_WORKAROUND_SCALE and then manually scale painter devices or calculations based on the resultant font metrics. Failure to do so will result in poor quality text rendering at small font sizes.

Since: QGIS 3.2

Definition at line 309 of file qgstextrenderer.cpp.

◆ sizeToPixel()

int QgsTextRenderer::sizeToPixel	(	double	size,
		const QgsRenderContext &	c,
		Qgis::RenderUnit	unit,
		const QgsMapUnitScale &	mapUnitScale = `QgsMapUnitScale()`
	)

static

Calculates pixel size (considering output size should be in pixel or map units, scale factors and optionally oversampling)

Parameters

size	size to convert
c	rendercontext
unit	size units
mapUnitScale	a mapUnitScale clamper

Returns: font pixel size

Definition at line 77 of file qgstextrenderer.cpp.

◆ textHeight() [1/2]

double QgsTextRenderer::textHeight	(	const QgsRenderContext &	context,
		const QgsTextFormat &	format,
		const QStringList &	textLines,
		Qgis::TextLayoutMode	mode = `Qgis::TextLayoutMode::Point`,
		QFontMetricsF *	fontMetrics = `nullptr`,
		Qgis::TextRendererFlags	flags = `Qgis::TextRendererFlags()`,
		double	maxLineWidth = `0`
	)

static

Returns the height of a text based on a given format.

Parameters

context	render context
format	text format
textLines	list of lines of text to calculate width from
mode	draw mode
fontMetrics	font metrics
flags	text renderer flags (since QGIS 3.24)
maxLineWidth	maximum line width, in painter units. Used when the Qgis::TextRendererFlag::WrapLines flag is used (since QGIS 3.24)

Definition at line 618 of file qgstextrenderer.cpp.

◆ textHeight() [2/2]

double QgsTextRenderer::textHeight	(	const QgsRenderContext &	context,
		const QgsTextFormat &	format,
		QChar	character,
		bool	includeEffects = `false`
	)

static

Returns the height of a character when rendered with the specified text format.

Parameters

context	render context
format	text format
character	character to determine height of. If character is invalid, then the maximum character height will be returned.
includeEffects	if `true`, then the size of formatting effects such as buffers and shadows will be considered in the returned height. If `false`, then the returned size considers the character only.

Since: QGIS 3.16

Definition at line 643 of file qgstextrenderer.cpp.

◆ textRequiresWrapping()

bool QgsTextRenderer::textRequiresWrapping	(	const QgsRenderContext &	context,
		const QString &	text,
		double	width,
		const QgsTextFormat &	format
	)

static

Returns true if the specified text requires line wrapping in order to fit within the specified width (in painter units).

See also: wrappedText()

Since: QGIS 3.24

Definition at line 690 of file qgstextrenderer.cpp.

◆ textWidth()

double QgsTextRenderer::textWidth	(	const QgsRenderContext &	context,
		const QgsTextFormat &	format,
		const QStringList &	textLines,
		QFontMetricsF *	fontMetrics = `nullptr`
	)

static

Returns the width of a text based on a given format.

Parameters

context	render context
format	text format
textLines	list of lines of text to calculate width from
fontMetrics	font metrics

Definition at line 589 of file qgstextrenderer.cpp.

◆ wrappedText()

QStringList QgsTextRenderer::wrappedText	(	const QgsRenderContext &	context,
		const QString &	text,
		double	width,
		const QgsTextFormat &	format
	)

static

Wraps a text string to multiple lines, such that each individual line will fit within the specified width (in painter units).

See also: textRequiresWrapping()

Since: QGIS 3.24

Definition at line 700 of file qgstextrenderer.cpp.

Friends And Related Function Documentation

◆ QgsLabelPreview

friend class QgsLabelPreview

friend

Definition at line 427 of file qgstextrenderer.h.

◆ QgsVectorLayerLabelProvider

friend class QgsVectorLayerLabelProvider

friend

Definition at line 426 of file qgstextrenderer.h.

Member Data Documentation

◆ FONT_WORKAROUND_SCALE

constexpr double QgsTextRenderer::FONT_WORKAROUND_SCALE = 10

staticconstexpr

Scale factor for upscaling font sizes and downscaling destination painter devices.

Using this scale factor and manually adjusting any font metric based calculations results in more stable font metrics and sizes for small font sizes.

Since: QGIS 3.16

Definition at line 265 of file qgstextrenderer.h.

The documentation for this class was generated from the following files:

/build/qgis-3.30.0+99sid/src/core/textrenderer/qgstextrenderer.h
/build/qgis-3.30.0+99sid/src/core/textrenderer/qgstextrenderer.cpp

Static Public Member Functions

Static Public Attributes

Friends

Detailed Description

Member Function Documentation

◆ convertQtHAlignment()

◆ convertQtVAlignment()

◆ drawDocument()

◆ drawPart() [1/2]

◆ drawPart() [2/2]

◆ drawText() [1/2]

◆ drawText() [2/2]

◆ fontMetrics()

◆ sizeToPixel()

◆ textHeight() [1/2]

◆ textHeight() [2/2]

◆ textRequiresWrapping()

◆ textWidth()

◆ wrappedText()

Friends And Related Function Documentation

◆ QgsLabelPreview

◆ QgsVectorLayerLabelProvider

Member Data Documentation

◆ FONT_WORKAROUND_SCALE