Class: QgsLayoutUtils

class qgis.core.QgsLayoutUtils

Bases: sip.wrapper

Utilities for layouts.

Methods

calculatePrettySize

Calculates a “pretty” size which falls between the range [minimumSize, maximumSize].

createRenderContextForLayout

Creates a render context suitable for the specified layout and painter destination.

createRenderContextForMap

Creates a render context suitable for the specified layout map and painter destination.

decodePaperOrientation

Decodes a string representing a paper orientation and returns the decoded orientation.

drawText

Draws text on a painter at a specific position, taking care of layout specific issues (calculation to pixel, scaling of font and painter to work around Qt font bugs).

fontAscentMM

Calculates a font ascent in millimeters, including workarounds for QT font rendering issues.

fontDescentMM

Calculate a font descent in millimeters, including workarounds for QT font rendering issues.

fontHeightCharacterMM

Calculate a font height in millimeters of a single character, including workarounds for QT font rendering issues.

fontHeightMM

Calculate a font height in millimeters, including workarounds for QT font rendering issues.

largestRotatedRectWithinBounds

Calculates the largest scaled version of originalRect which fits within boundsRect, when it is rotated by the a specified rotation amount.

mapLayerFromString

Resolves a string into a map layer from a given project.

normalizedAngle

Ensures that an angle (in degrees) is in the range 0 <= angle < 360.

relativePosition

Returns a scaled position given a before and after range

relativeResizeRect

Resizes a QRectF relative to a resized bounding rectangle.

rotate

Rotates a point / vector around the origin.

scaleFactorFromItemStyle

Extracts the scale factor from an item style.

scaledFontPixelSize

Returns a font where size is set in points and the size has been upscaled with FONT_WORKAROUND_SCALE to workaround QT font rendering bugs.

snappedAngle

Snaps an angle (in degrees) to its closest 45 degree angle.

textHeightMM

Calculate a font height in millimeters for a text string, including workarounds for QT font rendering issues.

textWidthMM

Calculate a font width in millimeters for a text string, including workarounds for QT font rendering issues.

calculatePrettySize(minimumSize: float, maximumSize: float) → float

Calculates a “pretty” size which falls between the range [minimumSize, maximumSize].

This method will return an optimal round number which falls within the given range, finding the largest “pretty” number possible.

New in version 3.10.

Parameters
  • minimumSize (float) –

  • maximumSize (float) –

Return type

float

createRenderContextForLayout(layout: QgsLayout, painter: QPainter, dpi: float = -1) → QgsRenderContext

Creates a render context suitable for the specified layout and painter destination. This method returns a new QgsRenderContext which matches the scale and settings from the layout’s QgsLayout.referenceMap() If the dpi argument is not specified then the dpi will be taken from the destination painter device.

Parameters
  • layout (QgsLayout) –

  • painter (QPainter) –

  • dpi (float = -1) –

Return type

QgsRenderContext

createRenderContextForMap(map: QgsLayoutItemMap, painter: QPainter, dpi: float = -1) → QgsRenderContext

Creates a render context suitable for the specified layout map and painter destination. This method returns a new QgsRenderContext which matches the scale and settings of the target map. If the dpi argument is not specified then the dpi will be taken from the destination painter device.

Parameters
Return type

QgsRenderContext

decodePaperOrientation(string: str) → Tuple[QgsLayoutItemPage.Orientation, bool]

Decodes a string representing a paper orientation and returns the decoded orientation. If the string was correctly decoded, ok will be set to True.

Parameters

string (str) –

Return type

Tuple[QgsLayoutItemPage.Orientation, bool]

drawText(painter: QPainter, position: Union[QPointF, QPoint], text: str, font: QFont, color: Union[QColor, Qt.GlobalColor, QGradient] = QColor())

Draws text on a painter at a specific position, taking care of layout specific issues (calculation to pixel, scaling of font and painter to work around Qt font bugs).

If color is specified, text will be rendered in that color. If not specified, the current painter pen color will be used instead.

drawText(painter: QPainter, rectangle: QRectF, text: str, font: QFont, color: Union[QColor, Qt.GlobalColor, QGradient] = QColor(), halignment: Qt.AlignmentFlag = Qt.AlignLeft, valignment: Qt.AlignmentFlag = Qt.AlignTop, flags: int = Qt.TextWordWrap) Draws text on a painter within a rectangle, taking care of layout specific issues (calculation to pixel, scaling of font and painter to work around Qt font bugs).

If color is specified, text will be rendered in that color. If not specified, the current painter pen color will be used instead.

The text alignment within rectangle can be set via the halignment and valignment arguments.

The flags parameter allows for passing Qt.TextFlags to control appearance of rendered text.

Parameters
  • painter (QPainter) –

  • position (Union[QPointF) –

  • text (str) –

  • font (QFont) –

  • color (Union[QColor) –

fontAscentMM(font: QFont) → float

Calculates a font ascent in millimeters, including workarounds for QT font rendering issues.

See also

fontDescentMM()

See also

fontHeightMM()

See also

textWidthMM()

Parameters

font (QFont) –

Return type

float

fontDescentMM(font: QFont) → float

Calculate a font descent in millimeters, including workarounds for QT font rendering issues.

See also

fontAscentMM()

See also

fontHeightMM()

See also

textWidthMM()

Parameters

font (QFont) –

Return type

float

fontHeightCharacterMM(font: QFont, character: str) → float

Calculate a font height in millimeters of a single character, including workarounds for QT font rendering issues.

See also

fontAscentMM()

See also

fontDescentMM()

See also

fontHeightMM()

See also

textWidthMM()

Parameters
  • font (QFont) –

  • character (str) –

Return type

float

fontHeightMM(font: QFont) → float

Calculate a font height in millimeters, including workarounds for QT font rendering issues. The font height is the font ascent + descent + 1 (for the baseline).

See also

fontAscentMM()

See also

fontDescentMM()

See also

textWidthMM()

Parameters

font (QFont) –

Return type

float

largestRotatedRectWithinBounds(originalRect: QRectF, boundsRect: QRectF, rotation: float) → QRectF

Calculates the largest scaled version of originalRect which fits within boundsRect, when it is rotated by the a specified rotation amount.

Parameters
  • originalRect (QRectF) – QRectF to be rotated and scaled

  • boundsRect (QRectF) – QRectF specifying the bounds which the rotated and scaled rectangle must fit within

  • rotation (float) – the rotation in degrees to be applied to the rectangle

Return type

QRectF

Returns

largest scaled version of the rectangle possible

mapLayerFromString(string: str, project: QgsProject) → QgsMapLayer

Resolves a string into a map layer from a given project. Attempts different forms of layer matching such as matching by layer id or layer name.

Layer names are matched using a case-insensitive check, ONLY if an exact case match was not found.

New in version 3.2.

Parameters
Return type

QgsMapLayer

normalizedAngle(angle: float, allowNegative: bool = False) → float

Ensures that an angle (in degrees) is in the range 0 <= angle < 360. If allowNegative is True then angles between (-360, 360) are allowed. If False, angles are converted to positive angles in the range [0, 360).

Parameters
  • angle (float) –

  • allowNegative (bool = False) –

Return type

float

relativePosition(position: float, beforeMin: float, beforeMax: float, afterMin: float, afterMax: float) → float

Returns a scaled position given a before and after range

Parameters
  • position (float) – initial position within before range to scale

  • beforeMin (float) – minimum value in before range

  • beforeMax (float) – maximum value in before range

  • afterMin (float) – minimum value in after range

  • afterMax (float) – maximum value in after range

Return type

float

Returns

position scaled to range specified by afterMin and afterMax

relativeResizeRect(rectToResize: QRectF, boundsBefore: QRectF, boundsAfter: QRectF)

Resizes a QRectF relative to a resized bounding rectangle.

Parameters
  • rectToResize (QRectF) – QRectF to resize, contained within boundsBefore. The rectangle is linearly scaled to retain its relative position and size within boundsAfter.

  • boundsBefore (QRectF) – QRectF of bounds before resize

  • boundsAfter (QRectF) – QRectF of bounds after resize

rotate(angle: float) → Tuple[float, float]

Rotates a point / vector around the origin.

Parameters
  • angle (float) – rotation angle in degrees, counterclockwise

  • x – in/out: x coordinate before / after the rotation

  • y – in/out: y coordinate before / after the rotation

Return type

Tuple[float, float]

scaleFactorFromItemStyle(style: QStyleOptionGraphicsItem) → float

Extracts the scale factor from an item style.

Parameters

style (QStyleOptionGraphicsItem) –

Return type

float

scaledFontPixelSize(font: QFont) → QFont

Returns a font where size is set in points and the size has been upscaled with FONT_WORKAROUND_SCALE to workaround QT font rendering bugs. Returns a font with size set in pixels.

Parameters

font (QFont) –

Return type

QFont

snappedAngle(angle: float) → float

Snaps an angle (in degrees) to its closest 45 degree angle.

Return type

float

Returns

angle snapped to 0, 45/90/135/180/225/270 or 315 degrees

Parameters

angle (float) –

textHeightMM(font: QFont, text: str, multiLineHeight: float = 1) → float

Calculate a font height in millimeters for a text string, including workarounds for QT font rendering issues. Note that this method uses a non-standard measure of text height, where only the font ascent is considered for the first line of text.

The multiLineHeight parameter specifies the line spacing factor.

See also

textWidthMM()

Parameters
  • font (QFont) –

  • text (str) –

  • multiLineHeight (float = 1) –

Return type

float

textWidthMM(font: QFont, text: str) → float

Calculate a font width in millimeters for a text string, including workarounds for QT font rendering issues.

See also

fontAscentMM()

See also

fontDescentMM()

See also

fontHeightMM()

See also

textHeightMM()

Parameters
  • font (QFont) –

  • text (str) –

Return type

float