QGIS API Documentation  3.11.0-Master (68611307d7)
Classes | Public Types | Static Public Member Functions | Friends | List of all members
QgsTextRenderer Class Reference

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

#include <qgstextrenderer.h>

Public Types

enum  DrawMode { Rect = 0, Point, Label }
 Draw mode to calculate width and height. More...
 
enum  HAlignment { AlignLeft = 0, AlignCenter, AlignRight }
 Horizontal alignment. More...
 
enum  TextPart { Text = 0, Buffer, Background, Shadow }
 Components of text. More...
 

Static Public Member Functions

static void drawPart (const QRectF &rect, double rotation, HAlignment alignment, const QStringList &textLines, QgsRenderContext &context, const QgsTextFormat &format, TextPart part, bool drawAsOutlines=true)
 Draws a single component of rendered text using the specified settings. More...
 
static void drawPart (QPointF origin, double rotation, HAlignment alignment, const QStringList &textLines, QgsRenderContext &context, const QgsTextFormat &format, TextPart part, bool drawAsOutlines=true)
 Draws a single component of rendered text using the specified settings. More...
 
static void drawText (const QRectF &rect, double rotation, HAlignment alignment, const QStringList &textLines, QgsRenderContext &context, const QgsTextFormat &format, bool drawAsOutlines=true)
 Draws text within a rectangle using the specified settings. More...
 
static void drawText (QPointF point, double rotation, HAlignment 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)
 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, QgsUnitTypes::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, DrawMode mode, QFontMetricsF *fontMetrics=nullptr)
 Returns the height of a text based on a given format. 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...
 

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 1620 of file qgstextrenderer.h.

Member Enumeration Documentation

◆ DrawMode

Draw mode to calculate width and height.

Enumerator
Rect 

Text within rectangle draw mode.

Point 

Text at point of origin draw mode.

Label 

Label-specific draw mode.

Definition at line 1625 of file qgstextrenderer.h.

◆ HAlignment

Horizontal alignment.

Enumerator
AlignLeft 

Left align.

AlignCenter 

Center align.

AlignRight 

Right align.

Definition at line 1642 of file qgstextrenderer.h.

◆ TextPart

Components of text.

Enumerator
Text 

Text component.

Buffer 

Buffer component.

Background 

Background shape.

Shadow 

Drop shadow.

Definition at line 1633 of file qgstextrenderer.h.

Member Function Documentation

◆ drawPart() [1/2]

void QgsTextRenderer::drawPart ( const QRectF &  rect,
double  rotation,
HAlignment  alignment,
const QStringList &  textLines,
QgsRenderContext context,
const QgsTextFormat format,
QgsTextRenderer::TextPart  part,
bool  drawAsOutlines = true 
)
static

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

Parameters
rectdestination rectangle for text
rotationtext rotation
alignmenthorizontal alignment
textLineslist of lines of text to draw
contextrender context
formattext format
partcomponent 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)
drawAsOutlinesset 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 2660 of file qgstextrenderer.cpp.

◆ drawPart() [2/2]

void QgsTextRenderer::drawPart ( QPointF  origin,
double  rotation,
QgsTextRenderer::HAlignment  alignment,
const QStringList &  textLines,
QgsRenderContext context,
const QgsTextFormat format,
QgsTextRenderer::TextPart  part,
bool  drawAsOutlines = true 
)
static

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

Parameters
originorigin for start of text. Y coordinate will be used as baseline.
rotationtext rotation
alignmenthorizontal alignment
textLineslist of lines of text to draw
contextrender context
formattext format
partcomponent 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)
drawAsOutlinesset 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 2724 of file qgstextrenderer.cpp.

◆ drawText() [1/2]

void QgsTextRenderer::drawText ( const QRectF &  rect,
double  rotation,
QgsTextRenderer::HAlignment  alignment,
const QStringList &  textLines,
QgsRenderContext context,
const QgsTextFormat format,
bool  drawAsOutlines = true 
)
static

Draws text within a rectangle using the specified settings.

Parameters
rectdestination rectangle for text
rotationtext rotation
alignmenthorizontal alignment
textLineslist of lines of text to draw
contextrender context
formattext format
drawAsOutlinesset 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 2599 of file qgstextrenderer.cpp.

◆ drawText() [2/2]

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

Draws text at a point origin using the specified settings.

Parameters
pointorigin of text
rotationtext rotation
alignmenthorizontal alignment
textLineslist of lines of text to draw
contextrender context
formattext format
drawAsOutlinesset 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 2619 of file qgstextrenderer.cpp.

◆ fontMetrics()

QFontMetricsF QgsTextRenderer::fontMetrics ( QgsRenderContext context,
const QgsTextFormat format 
)
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.

Since
QGIS 3.2

Definition at line 2768 of file qgstextrenderer.cpp.

◆ sizeToPixel()

int QgsTextRenderer::sizeToPixel ( double  size,
const QgsRenderContext c,
QgsUnitTypes::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
sizesize to convert
crendercontext
unitsize units
mapUnitScalea mapUnitScale clamper
Returns
font pixel size

Definition at line 2594 of file qgstextrenderer.cpp.

◆ textHeight()

double QgsTextRenderer::textHeight ( const QgsRenderContext context,
const QgsTextFormat format,
const QStringList &  textLines,
DrawMode  mode,
QFontMetricsF *  fontMetrics = nullptr 
)
static

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

Parameters
contextrender context
formattext format
textLineslist of lines of text to calculate width from
modedraw mode
fontMetricsfont metrics

Definition at line 2978 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
contextrender context
formattext format
textLineslist of lines of text to calculate width from
fontMetricsfont metrics

Definition at line 2936 of file qgstextrenderer.cpp.

Friends And Related Function Documentation

◆ QgsLabelPreview

friend class QgsLabelPreview
friend

Definition at line 1831 of file qgstextrenderer.h.

◆ QgsVectorLayerLabelProvider

friend class QgsVectorLayerLabelProvider
friend

Definition at line 1830 of file qgstextrenderer.h.


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