IWarningCallback class

Implement this interface if you want to have your own custom method called to capture loss of fidelity warnings that can occur during document loading or saving.

Methods

Name	Description
warning(info)	Aspose.Words invokes this method when it encounters some issue during document loading or saving that might result in loss of formatting or data fidelity.

Examples

Shows how to use the IWarningCallback interface to monitor font substitution warnings.

doc = aw.Document()
builder = aw.DocumentBuilder(doc=doc)
builder.font.name = 'Times New Roman'
builder.writeln('Hello world!')
callback = self.FontSubstitutionWarningCollector()
doc.warning_callback = callback
# Store the current collection of font sources, which will be the default font source for every document
# for which we do not specify a different font source.
original_font_sources = aw.fonts.FontSettings.default_instance.get_fonts_sources()
# For testing purposes, we will set Aspose.Words to look for fonts only in a folder that does not exist.
aw.fonts.FontSettings.default_instance.set_fonts_folder('', False)
# When rendering the document, there will be no place to find the "Times New Roman" font.
# This will cause a font substitution warning, which our callback will detect.
doc.save(file_name=ARTIFACTS_DIR + 'FontSettings.SubstitutionWarning.pdf')
aw.fonts.FontSettings.default_instance.set_fonts_sources(sources=original_font_sources)
self.assertEqual(1, callback.font_substitution_warnings.count)
self.assertTrue(callback.font_substitution_warnings[0].warning_type == aw.WarningType.FONT_SUBSTITUTION)
self.assertTrue(callback.font_substitution_warnings[0].description == "Font 'Times New Roman' has not been found. Using 'Fanwood' font instead. Reason: first available font.")

Shows how to set the property for finding the closest match for a missing font from the available font sources.

# Open a document that contains text formatted with a font that does not exist in any of our font sources.
doc = aw.Document(file_name=MY_DIR + 'Missing font.docx')
# Assign a callback for handling font substitution warnings.
warning_collector = aw.WarningInfoCollection()
doc.warning_callback = warning_collector
# Set a default font name and enable font substitution.
font_settings = aw.fonts.FontSettings()
font_settings.substitution_settings.default_font_substitution.default_font_name = 'Arial'
font_settings.substitution_settings.font_info_substitution.enabled = True
# Original font metrics should be used after font substitution.
doc.layout_options.keep_original_font_metrics = True
# We will get a font substitution warning if we save a document with a missing font.
doc.font_settings = font_settings
doc.save(file_name=ARTIFACTS_DIR + 'FontSettings.EnableFontSubstitution.pdf')
for info in warning_collector:
    if info.warning_type == aw.WarningType.FONT_SUBSTITUTION:
        print(info.description)

Shows how to use the IWarningCallback interface to monitor font substitution warnings (FontSubstitutionWarningCollector).

class FontSubstitutionWarningCollector(aw.IWarningCallback):

    def __init__(self):
        self.font_substitution_warnings = aw.WarningInfoCollection()

    def warning(self, info):
        if info.warning_type == aw.WarningType.FONT_SUBSTITUTION:
            self.font_substitution_warnings.warning(info)

Shows added a fallback to bitmap rendering and changing type of warnings about unsupported metafile records.

doc = aw.Document(file_name=MY_DIR + 'WMF with image.docx')
metafile_rendering_options = aw.saving.MetafileRenderingOptions()
# Set the "EmulateRasterOperations" property to "false" to fall back to bitmap when
# it encounters a metafile, which will require raster operations to render in the output PDF.
metafile_rendering_options.emulate_raster_operations = False
# Set the "RenderingMode" property to "VectorWithFallback" to try to render every metafile using vector graphics.
metafile_rendering_options.rendering_mode = aw.saving.MetafileRenderingMode.VECTOR_WITH_FALLBACK
# Create a "PdfSaveOptions" object that we can pass to the document's "Save" method
# to modify how that method converts the document to .PDF and applies the configuration
# in our MetafileRenderingOptions object to the saving operation.
save_options = aw.saving.PdfSaveOptions()
save_options.metafile_rendering_options = metafile_rendering_options
callback = self.HandleDocumentWarnings()
doc.warning_callback = callback
doc.save(file_name=ARTIFACTS_DIR + 'PdfSaveOptions.HandleBinaryRasterWarnings.pdf', save_options=save_options)
self.assertEqual(1, callback.warnings.count)
self.assertEqual("'R2_XORPEN' binary raster operation is not supported.", callback.warnings[0].description)

Shows added a fallback to bitmap rendering and changing type of warnings about unsupported metafile records (HandleDocumentWarnings).

class HandleDocumentWarnings(aw.IWarningCallback):

    def __init__(self):
        self.warnings = aw.WarningInfoCollection()

    def warning(self, info):
        if info.warning_type == aw.WarningType.MINOR_FORMATTING_LOSS:
            print('Unsupported operation: ' + info.description)
            self.warnings.warning(info)

IWarningCallback class