Class: QgsRasterTransparency

Defines the list of pixel values to be considered as transparent or semi transparent when rendering rasters.

Methods

alphaValue	Returns the transparency value for a single value pixel.
initializeTransparentPixelList	Resets the transparency list to a single value.
isEmpty	True if there are no entries in the pixel lists except the nodata value
opacityForRgbValues	Returns the opacity (as a value from 0 to 1) for a set of RGB pixel values.
opacityForValue	Returns the opacity (as a value from 0 to 1) for a single value pixel.
readXml	Reads the transparency information from an XML document.
setTransparentSingleValuePixelList	Sets the transparent single value pixel list, replacing the whole existing list.
setTransparentThreeValuePixelList	Sets the transparent three value pixel list, replacing the whole existing list.
transparentSingleValuePixelList	Returns the transparent single value pixel list.
transparentThreeValuePixelList	Returns the transparent three value pixel list.
writeXml	Writes the transparency information to an XML document.

class qgis.core.QgsRasterTransparency

Bases: object

class TransparentSingleValuePixel

Bases: object

Defines the transparency for a range of single-band pixel values.

includeMaximum

True if pixels matching the max value should be considered transparent, or False if only pixels less than the max value should be transparent.

Added in version 3.38.

includeMinimum

True if pixels matching the min value should be considered transparent, or False if only pixels greater than the min value should be transparent.

Added in version 3.38.

max

Maximum pixel value to include in range.

min

Minimum pixel value to include in range.

opacity

Opacity for pixel, between 0 and 1.0.

Added in version 3.38.

property percentTransparent

class TransparentThreeValuePixel

Bases: object

Defines the transparency for a RGB pixel value.

blue

Blue pixel value.

fuzzyToleranceBlue

Fuzzy tolerance for blue values.

If non zero, the pixel’s blue component can deviate from values specified in this object by a maximum of this tolerance amount.

Added in version 3.40.

fuzzyToleranceGreen

Fuzzy tolerance for green values.

If non zero, the pixel’s green component can deviate from values specified in this object by a maximum of this tolerance amount.

Added in version 3.40.

fuzzyToleranceRed

Fuzzy tolerance for red values.

If non zero, the pixel’s red component can deviate from values specified in this object by a maximum of this tolerance amount.

Added in version 3.40.

green

Green pixel value.

opacity

Opacity for pixel, between 0 and 1.0.

Added in version 3.38.

property percentTransparent

red

Red pixel value.

alphaValue(self, value: float, globalTransparency: int = 255) → int

Returns the transparency value for a single value pixel.

Searches through the transparency list, and if a match is found, the global transparency value is scaled by the stored transparency value.

Parameters:

• value (float) – the needle to search for in the transparency hay stack

• globalTransparency (int = 255) – the overall transparency level for the layer

Deprecated since version 3.40: Use opacityForValue() instead.

Return type:

int

alphaValue(self, redValue: float, greenValue: float, blueValue: float, globalTransparency: int = 255) → int

Returns the transparency value for a RGB pixel.

Searches through the transparency list, if a match is found, the global transparency value is scaled by the stored transparency value.

Parameters:

• redValue (float) – the red portion of the needle to search for in the transparency hay stack

• greenValue (float) – the green portion of the needle to search for in the transparency hay stack

• blueValue (float) – the green portion of the needle to search for in the transparency hay stack

• globalTransparency (int = 255) – the overall transparency level for the layer

Deprecated since version 3.40: Use opacityForRgbValues() instead.

Return type:

int

initializeTransparentPixelList(self, value: float)

Resets the transparency list to a single value.

Parameters:

value (float)

initializeTransparentPixelList(self, redValue: float, greenValue: float, blueValue: float)

Resets the transparency list to single red, green, and blue values.

Parameters:

• redValue (float)

• greenValue (float)

• blueValue (float)

isEmpty(self) → bool

True if there are no entries in the pixel lists except the nodata value

Return type:

bool

opacityForRgbValues(self, redValue: float, greenValue: float, blueValue: float) → float

Returns the opacity (as a value from 0 to 1) for a set of RGB pixel values.

Searches through the transparency list, and if a match is found, returns the opacity corresponding to the values. Returns 1 if no matches are found.

If any of the red, green or blue values are NaN, 0 will be returned.

Added in version 3.38.

Parameters:

• redValue (float)

• greenValue (float)

• blueValue (float)

Return type:

float

opacityForValue(self, value: float) → float

Returns the opacity (as a value from 0 to 1) for a single value pixel.

Searches through the transparency list, and if a match is found, returns the opacity corresponding to the value. Returns 1 if no matches are found.

Added in version 3.38.

Parameters:

value (float)

Return type:

float

readXml(self, elem: QDomElement)

Reads the transparency information from an XML document.

Parameters:

elem (QDomElement)

setTransparentSingleValuePixelList(self, newList: Iterable[QgsRasterTransparency.TransparentSingleValuePixel])

Sets the transparent single value pixel list, replacing the whole existing list.

See also

transparentSingleValuePixelList()

Parameters:

newList (Iterable[QgsRasterTransparency.TransparentSingleValuePixel])

setTransparentThreeValuePixelList(self, newList: Iterable[QgsRasterTransparency.TransparentThreeValuePixel])

Sets the transparent three value pixel list, replacing the whole existing list.

See also

transparentThreeValuePixelList()

Parameters:

newList (Iterable[QgsRasterTransparency.TransparentThreeValuePixel])

transparentSingleValuePixelList(self) → List[QgsRasterTransparency.TransparentSingleValuePixel]

Returns the transparent single value pixel list.

See also

setTransparentSingleValuePixelList()

Return type:

List[QgsRasterTransparency.TransparentSingleValuePixel]

transparentThreeValuePixelList(self) → List[QgsRasterTransparency.TransparentThreeValuePixel]

Returns the transparent three value pixel list.

See also

setTransparentThreeValuePixelList()

Return type:

List[QgsRasterTransparency.TransparentThreeValuePixel]

writeXml(self, doc: QDomDocument, parentElem: QDomElement)

Writes the transparency information to an XML document.

Parameters:

• doc (QDomDocument)

• parentElem (QDomElement)