sw/qa/core/accessibilitycheck/AccessibilityCheckTest.cxx | 28 ++++++++++++++
sw/qa/core/accessibilitycheck/data/ContrastTestFail.odt |binary
sw/qa/core/accessibilitycheck/data/ContrastTestOK.odt |binary
sw/source/core/access/AccessibilityCheck.cxx | 29 ++++++++++++++-
4 files changed, 56 insertions(+), 1 deletion(-)
New commits:
commit 99c04ba30e5dbc8bdc7a3e920536b0c432c39797
Author: Michael Weghorn <m.wegh...@posteo.de>
AuthorDate: Mon Dec 9 10:11:59 2024 +0100
Commit: Michael Weghorn <m.wegh...@posteo.de>
CommitDate: Thu Dec 12 09:52:15 2024 +0100
tdf#164247 sw a11y check: Adhere to WCAG contrast threshold for large text
Quoting WCAG 2.2 "Success Criterion 1.4.3 Contrast (Minimum)" [1]:
> The visual presentation of text and images of text has a contrast
> ratio of at least 4.5:1, except for the following:
>
> Large Text
>
> Large-scale text and images of large-scale text have a contrast
> ratio of at least 3:1;
Regarding large text, the corresponding "Understanding SC 1.4.3" [2]
clarifies:
> Text that is larger and has wider character strokes is easier to read at
> lower contrast. The contrast requirement for larger text is therefore
> lower. This allows authors to use a wider range of color choices for
> large text, which is helpful for design of pages, particularly titles.
> 18 point text or 14 point bold text is judged to be large enough to
> require a lower contrast ratio.
Therefore, lower the text contrast requirement in
Writer's accessibility check from 4.5 to 3.0 for
text that is considered large according to that
specification.
Add a unit test with 2 test documents:
* one that adheres to the requirements and would have triggered false
positives without this change in place
(sw/qa/core/accessibilitycheck/data/ContrastTestOK.odt)
* one that doesn't adhere to the requirements and still fails the
check, as it should
(sw/qa/core/accessibilitycheck/data/ContrastTestFail.odt)
[1] https://www.w3.org/TR/WCAG22/#contrast-minimum
[2] https://www.w3.org/WAI/WCAG22/Understanding/contrast-minimum.html
Change-Id: I398f72aa5bdcd77c42834632575d6465a5ecd586
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/178127
Reviewed-by: Michael Weghorn <m.wegh...@posteo.de>
Tested-by: Jenkins
Reviewed-by: Balazs Varga <balazs.varga.ext...@allotropia.de>
(cherry picked from commit a4b03fce93fce7672be40b57d30797ac36ca67c9)
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/178169
diff --git a/sw/qa/core/accessibilitycheck/AccessibilityCheckTest.cxx
b/sw/qa/core/accessibilitycheck/AccessibilityCheckTest.cxx
index d15eeaf70da9..fc0aa008f4b3 100644
--- a/sw/qa/core/accessibilitycheck/AccessibilityCheckTest.cxx
+++ b/sw/qa/core/accessibilitycheck/AccessibilityCheckTest.cxx
@@ -306,6 +306,34 @@ CPPUNIT_TEST_FIXTURE(AccessibilityCheckTest,
testStylesWithHeader)
CPPUNIT_ASSERT_EQUAL(sfx::AccessibilityIssueID::DIRECT_FORMATTING,
aIssues[4]->m_eIssueID);
}
+// Text contrast tests
+// see https://www.w3.org/WAI/WCAG22/Understanding/contrast-minimum.html
+CPPUNIT_TEST_FIXTURE(AccessibilityCheckTest, testCheckTextContrast)
+{
+ // first test doc has these issues:
+ // * normal text with contrast < 4.5
+ // * large text with contrast < 3.0
+ // * bold text with font size 13 (i.e. not considered large) with contrast
< 4.5
+ createSwDoc("ContrastTestFail.odt");
+ SwDoc* pDoc = getSwDoc();
+ sw::AccessibilityCheck aCheck(pDoc);
+ aCheck.check();
+ auto& aIssues = aCheck.getIssueCollection().getIssues();
+ CPPUNIT_ASSERT_EQUAL(size_t(3), aIssues.size());
+
+ // second test doc has large text with contrast between 3.0 and 4.5,
+ // which is sufficient for large text
+ // both of these are considered large text according to the spec:
+ // * non-bold text font with size 18
+ // * bold text with font size 14
+ createSwDoc("ContrastTestOK.odt");
+ SwDoc* pDocOK = getSwDoc();
+ sw::AccessibilityCheck aCheckOK(pDocOK);
+ aCheckOK.check();
+ auto& aIssuesOK = aCheckOK.getIssueCollection().getIssues();
+ CPPUNIT_ASSERT_EQUAL(size_t(0), aIssuesOK.size());
+}
+
namespace
{
std::vector<std::shared_ptr<sfx::AccessibilityIssue>>
diff --git a/sw/qa/core/accessibilitycheck/data/ContrastTestFail.odt
b/sw/qa/core/accessibilitycheck/data/ContrastTestFail.odt
new file mode 100644
index 000000000000..4f898942e37f
Binary files /dev/null and
b/sw/qa/core/accessibilitycheck/data/ContrastTestFail.odt differ
diff --git a/sw/qa/core/accessibilitycheck/data/ContrastTestOK.odt
b/sw/qa/core/accessibilitycheck/data/ContrastTestOK.odt
new file mode 100644
index 000000000000..2f47148838a2
Binary files /dev/null and
b/sw/qa/core/accessibilitycheck/data/ContrastTestOK.odt differ
diff --git a/sw/source/core/access/AccessibilityCheck.cxx
b/sw/source/core/access/AccessibilityCheck.cxx
index 0d63ed192696..f54f348786f3 100644
--- a/sw/source/core/access/AccessibilityCheck.cxx
+++ b/sw/source/core/access/AccessibilityCheck.cxx
@@ -21,6 +21,7 @@
#include <svx/svdpage.hxx>
#include <sortedobjs.hxx>
#include <swtable.hxx>
+#include <com/sun/star/awt/FontWeight.hpp>
#include <com/sun/star/frame/XModel.hpp>
#include <com/sun/star/text/XTextContent.hpp>
#include <com/sun/star/document/XDocumentPropertiesSupplier.hpp>
@@ -490,6 +491,32 @@ double calculateContrastRatio(Color const& rColor1, Color
const& rColor2)
return (aMinMax.second + 0.05) / (aMinMax.first + 0.05);
}
+// Determine required minimum contrast ratio for text with the given properties
+// according to
https://www.w3.org/WAI/WCAG22/Understanding/contrast-minimum.html
+// * 3.0 for large text (font size >= 18 or bold and font size >= 14)
+// * 4.5 otherwise
+double minimumContrastRatio(const uno::Reference<beans::XPropertySet>&
xProperties)
+{
+ double fMinimumContrastRatio = 4.5;
+ double fFontSize = 0;
+ if (xProperties->getPropertyValue(u"CharHeight"_ustr) >>= fFontSize)
+ {
+ if (fFontSize >= 18)
+ fMinimumContrastRatio = 3.0;
+ else if (fFontSize >= 14)
+ {
+ double fCharWeight = 0;
+ if (xProperties->getPropertyValue(u"CharWeight"_ustr) >>=
fCharWeight)
+ {
+ if (fCharWeight == css::awt::FontWeight::BOLD
+ || fCharWeight == css::awt::FontWeight::ULTRABOLD)
+ fMinimumContrastRatio = 3.0;
+ }
+ }
+ }
+ return fMinimumContrastRatio;
+}
+
class TextContrastCheck : public NodeCheck
{
private:
@@ -609,7 +636,7 @@ private:
aBackgroundColor = COL_WHITE;
double fContrastRatio = calculateContrastRatio(aForegroundColor,
aBackgroundColor);
- if (fContrastRatio < 4.5)
+ if (fContrastRatio < minimumContrastRatio(xProperties))
{
auto pIssue = lclAddIssue(m_rIssueCollection,
SwResId(STR_TEXT_CONTRAST));
pIssue->setIssueObject(IssueObject::TEXT);
