Class: QgsRasterTransparency

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

class qgis.core.QgsRasterTransparency[source]

Bases: object

class TransparentSingleValuePixel

Bases: object

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

includeMaximum: bool
includeMinimum: bool
max: float
min: float
opacity: float
property percentTransparent
class TransparentThreeValuePixel

Bases: object

Defines the transparency for a RGB pixel value.

blue: float
fuzzyToleranceBlue: float
fuzzyToleranceGreen: float
fuzzyToleranceRed: float
green: float
opacity: float
property percentTransparent
red: float
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.

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 – the red portion of the needle to search for in the transparency hay stack

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

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

  • globalTransparency – 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.

initializeTransparentPixelList(self, redValue: float, greenValue: float, blueValue: float) Resets the transparency list to single red, green, and blue values.

Parameters:

value (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.

See also

transparentSingleValuePixelList()

Parameters:

newList (Iterable[QgsRasterTransparency.TransparentSingleValuePixel])

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

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)[source]

Writes the transparency information to an XML document.

Parameters:

  • doc (QDomDocument)

  • parentElem (QDomElement)