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[source]

Bases: object

class TransparentSingleValuePixel

Bases: object

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

includeMaximum: bool

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: bool

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: float

Maximum pixel value to include in range.

min: float

Minimum pixel value to include in range.

opacity: float

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: float

Blue pixel value.

fuzzyToleranceBlue: float

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: float

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: float

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: float

Green pixel value.

opacity: float

Opacity for pixel, between 0 and 1.0.

Added in version 3.38.

property percentTransparent
red: float

Red pixel value.

alphaValue(self, value: float, globalTransparency: int = 255) int[source]

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[source]

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)[source]

Resets the transparency list to a single value.

Parameters:

value (float)

initializeTransparentPixelList(self, redValue: float, greenValue: float, blueValue: float)[source]

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

Parameters:
  • redValue (float)

  • greenValue (float)

  • blueValue (float)

isEmpty(self) bool[source]

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[source]

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[source]

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)[source]

Reads the transparency information from an XML document.

Parameters:

elem (QDomElement)

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

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

Parameters:

newList (Iterable[QgsRasterTransparency.TransparentSingleValuePixel])

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

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

Parameters:

newList (Iterable[QgsRasterTransparency.TransparentThreeValuePixel])

transparentSingleValuePixelList(self) List[QgsRasterTransparency.TransparentSingleValuePixel]

Returns the transparent single value pixel list.

Return type:

List[QgsRasterTransparency.TransparentSingleValuePixel]

transparentThreeValuePixelList(self) List[QgsRasterTransparency.TransparentThreeValuePixel]

Returns the transparent three value pixel list.

Return type:

List[QgsRasterTransparency.TransparentThreeValuePixel]

writeXml(self, doc: QDomDocument, parentElem: QDomElement)[source]

Writes the transparency information to an XML document.

Parameters:
  • doc (QDomDocument)

  • parentElem (QDomElement)