Class: QgsRenderChecker

Helper class for unit tests that need to write an image and compare it to an expected result or render time.

class qgis.core.QgsRenderChecker

Bases: object

__init__()

Constructor for QgsRenderChecker.

__init__(a0: QgsRenderChecker)

Parameters:

a0 (QgsRenderChecker)

class Flag(*values)

Bases: IntEnum

Render checker flags.

Added in version 3.28.

• AvoidExportingRenderedImage: Avoids exporting rendered images to reports

• Silent: Don’t output non-critical messages to console

  Added in version 3.40.

AvoidExportingRenderedImage = 1

Silent = 2

class Flags

class Flags(f: QgsRenderChecker.Flags | QgsRenderChecker.Flag)

class Flags(a0: QgsRenderChecker.Flags)

Bases: object

compareImages(self, testName: str | None, mismatchCount: int = 0, renderedImageFile: str | None = '', flags: QgsRenderChecker.Flags | QgsRenderChecker.Flag = QgsRenderChecker.Flags()) → bool

Test using two arbitrary images (map renderer will not be used)

Parameters:

• testName (Optional[str]) – to be used as the basis for writing a file to e.g. /tmp/theTestName.png

• mismatchCount (int = 0) – defaults to 0. The number of pixels that are allowed to be different from the control image. In some cases rendering may be non-deterministic. This parameter allows you to account for that by providing a tolerance.

• renderedImageFile (Optional[str] = '') – to optionally override the output filename

• flags (Union[QgsRenderChecker.Flags, QgsRenderChecker.Flag] = QgsRenderChecker.Flags()) – render checker flags

Note

Make sure to call setExpectedImage and setRenderedImage first.

compareImages(self, testName: Optional[str], referenceImageFile: Optional[str], renderedImageFile: Optional[str], mismatchCount: int = 0, flags: Union[QgsRenderChecker.Flags, QgsRenderChecker.Flag] = QgsRenderChecker.Flags()) -> bool Test using two arbitrary images at the specified paths for equality.

Added in version 3.18.

Return type:

bool

controlImagePath(self) → str

Returns the base path containing the reference images.

This defaults to an internal QGIS test data path, but can be changed via setControlImagePath().

See also

setControlImagePath()

Return type:

str

dartMeasurements(self) → List[QgsDartMeasurement]

Gets access to buffered dash messages. Only will return something if you call enableDashBuffering( True ); before.

Return type:

List[QgsDartMeasurement]

Returns:

buffered dash messages

static drawBackground(image: QImage | None)

Draws a checkboard pattern for image backgrounds, so that opacity is visible without requiring a transparent background for the image

Parameters:

image (Optional[QImage])

elapsedTime(self) → int

Returns the total elapsed time for the rendering test.

Note

This only records time for actual render part.

Return type:

int

enableDashBuffering(self, enable: bool)

Call this to enable internal buffering of dash messages. You may later call dashMessages() to get access to the buffered messages. If disabled (default) dash messages will be sent immediately.

Parameters:

enable (bool) – Enable or disable buffering

expectedImageFile(self) → str

Returns the path to the expected image file

Return type:

str

Returns:

Path to the expected image file

imageToHash(self, imageFile: str | None) → str

Gets an md5 hash that uniquely identifies an image

Parameters:

imageFile (Optional[str])

Return type:

str

isKnownAnomaly(self, diffImageFile: str | None) → bool

Gets a list of all the anomalies. An anomaly is a rendered difference file where there is some red pixel content (indicating a render check mismatch), but where the output was still acceptable. If the render diff matches one of these anomalies we will still consider it to be acceptable.

Return type:

bool

Returns:

a bool indicating if the diff matched one of the anomaly files

Deprecated since version 3.40: Use the test mask system instead.

Parameters:

diffImageFile (Optional[str])

markdownReport(self, ignoreSuccess: bool = True) → str

Returns the markdown report describing the results of the test run.

If ignoreSuccess is True then the report will always be empty if the test was successful.

See also

report()

Added in version 3.34.

Parameters:

ignoreSuccess (bool = True)

Return type:

str

matchPercent(self) → float

Returns the percent of pixels which matched the control image.

Return type:

float

matchTarget(self) → int

Returns the total number of pixels in the control image.

Return type:

int

mismatchCount(self) → int

Returns the number of pixels which did not match the control image.

Return type:

int

renderedImage(self) → str

Returns the path of the rendered image generated by the test.

This method will return either the path set with setRenderedImage() or generated in runTest().

Return type:

str

report(self, ignoreSuccess: bool = True) → str

Returns the HTML report describing the results of the test run.

If ignoreSuccess is True then the report will always be empty if the test was successful.

See also

markdownReport()

Parameters:

ignoreSuccess (bool = True)

Return type:

str

runTest(self, testName: str | None, mismatchCount: int = 0, flags: QgsRenderChecker.Flags | QgsRenderChecker.Flag = QgsRenderChecker.Flags()) → bool

Test using renderer to generate the image to be compared.

Parameters:

• testName (Optional[str]) – to be used as the basis for writing a file to e.g. /tmp/theTestName.png

• mismatchCount (int = 0) – defaults to 0. The number of pixels that are allowed to be different from the control image. In some cases rendering may be non-deterministic. This parameter allows you to account for that by providing a tolerance.

• flags (Union[QgsRenderChecker.Flags, QgsRenderChecker.Flag] = QgsRenderChecker.Flags()) – render checker flags

Note

Make sure to call setExpectedImage and setMapRenderer first

Return type:

bool

setColorTolerance(self, colorTolerance: int)

Set tolerance for color components used by runTest() and compareImages(). Default value is 0.

Parameters:

colorTolerance (int) – is maximum difference for each color component including alpha to be considered correct.

setControlExtension(self, extension: str | None)

Sets file extension for the control image. By default it is “png”

Added in version 3.20.

Parameters:

extension (Optional[str])

setControlImagePath(self, path: str | None)

Sets the base path containing the reference images.

See also

controlImagePath()

Added in version 3.18.

Parameters:

path (Optional[str])

setControlName(self, name: str | None)

Sets the base directory name for the control image (with control image path suffixed).

The path to the image will be constructed like this: controlImagePath() + ‘/’ + control name + ‘/’ + control name + ‘.’ + extension (‘png’ by default)

Parameters:

name (Optional[str])

setControlPathPrefix(self, name: str | None)

Sets the path prefix where the control images are kept. This will be appended to controlImagePath().

Parameters:

name (Optional[str])

setControlPathSuffix(self, name: str | None)

Parameters:

name (Optional[str])

setElapsedTimeTarget(self, target: int)

Parameters:

target (int)

setExpectFail(self, expectFail: bool)

Sets whether the comparison is expected to fail.

Added in version 3.28.

Parameters:

expectFail (bool)

setMapSettings(self, mapSettings: QgsMapSettings)

Parameters:

mapSettings (QgsMapSettings)

setRenderedImage(self, imageFileName: str | None)

Sets the file name of the rendered image generated by the test.

Parameters:

imageFileName (Optional[str])

setSizeTolerance(self, xTolerance: int, yTolerance: int)

Sets the largest allowable difference in size between the rendered and the expected image.

Parameters:

• xTolerance (int) – x tolerance in pixels

• yTolerance (int) – y tolerance in pixels

static shouldGenerateReport() → bool

Returns True if a test report should be generated given the current environment.

Added in version 3.28.

Return type:

bool

static sourcePath() → str

Returns the path to the QGIS source code.

Added in version 3.36.

Return type:

str

static testReportDir() → QDir

Returns the directory to use for generating a test report.

Added in version 3.28.

Return type:

QDir