tdf#127423: Allow disabling default features in Font Features dialog

In OpenType fonts we have no way if detecting what features are on by
default and what not (short of hard-coding this, since HarfBuzz has no
API of giving us this information, and it is also not a fixed set
per-font, depends also on the text being shaped).

The dialog currently does not differentiate between a disabled feature
and unset feature. To make this distinction, feature value is now signed
and negative value means the feature is unset (i.e. the default is
used), and the checkbox is now a try state one to reflect this.

Change-Id: Iba5d13f02610e7b761677acc19872788c72afde1
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/138729
Tested-by: Jenkins
Reviewed-by: Tomaž Vajngerl <quikee@gmail.com>

2 files changed, 9 insertions, 6 deletions

diff --git a/cui/source/dialogs/FontFeaturesDialog.cxx b/cui/source/dialogs/FontFeaturesDialog.cxx
index 0d5d512bf053..53ca5f12f3c1 100644
--- a/cui/source/dialogs/FontFeaturesDialog.cxx
+++ b/cui/source/dialogs/FontFeaturesDialog.cxx
@@ -100,7 +100,7 @@ int FontFeaturesDialog::fillGrid(std::vector<vcl::font::Feature> const& rFontFea
 
         m_aFeatureItems.emplace_back(m_xContentGrid.get());
 
-        uint32_t nValue = 0;
+        int32_t nValue = 0;
         if (aExistingFeatures.find(nFontFeatureCode) != aExistingFeatures.end())
             nValue = aExistingFeatures.at(nFontFeatureCode);
         else
@@ -133,7 +133,10 @@ int FontFeaturesDialog::fillGrid(std::vector<vcl::font::Feature> const& rFontFea
         }
         else
         {
-            aCurrentItem.m_xCheck->set_active(nValue > 0);
+            if (nValue < 0)
+                aCurrentItem.m_xCheck->set_state(TRISTATE_INDET);
+            else
+                aCurrentItem.m_xCheck->set_state(nValue > 0 ? TRISTATE_TRUE : TRISTATE_FALSE);
             aCurrentItem.m_xCheck->set_label(aDefinition.getDescription());
             aCurrentItem.m_xCheck->connect_toggled(aCheckBoxToggleHandler);
             aCurrentItem.m_xCheck->show();
@@ -183,7 +186,7 @@ OUString FontFeaturesDialog::createFontNameWithFeatures()
     {
         if (rItem.m_xCheck->get_visible())
         {
-            if (sal_uInt32(rItem.m_xCheck->get_active()) != rItem.m_nDefault)
+            if (rItem.m_xCheck->get_state() != TRISTATE_INDET)
             {
                 if (!bFirst)
                     sNameSuffix.append(vcl::font::FeatureSeparator);
@@ -191,7 +194,7 @@ OUString FontFeaturesDialog::createFontNameWithFeatures()
                     bFirst = false;
 
                 sNameSuffix.append(vcl::font::featureCodeAsString(rItem.m_aFeatureCode));
-                if (!rItem.m_xCheck->get_active())
+                if (rItem.m_xCheck->get_state() == TRISTATE_FALSE)
                     sNameSuffix.append("=0");
             }
         }
diff --git a/cui/source/inc/FontFeaturesDialog.hxx b/cui/source/inc/FontFeaturesDialog.hxx
index f542566ae2f5..6b30a33111b2 100644
--- a/cui/source/inc/FontFeaturesDialog.hxx
+++ b/cui/source/inc/FontFeaturesDialog.hxx
@@ -22,7 +22,7 @@ struct FontFeatureItem
 {
     FontFeatureItem(weld::Widget* pParent)
         : m_aFeatureCode(0)
-        , m_nDefault(0)
+        , m_nDefault(-1)
         , m_xBuilder(Application::CreateBuilder(pParent, "cui/ui/fontfragment.ui"))
         , m_xContainer(m_xBuilder->weld_widget("fontentry"))
         , m_xText(m_xBuilder->weld_label("label"))
@@ -32,7 +32,7 @@ struct FontFeatureItem
     }
 
     sal_uInt32 m_aFeatureCode;
-    sal_uInt32 m_nDefault;
+    sal_Int32 m_nDefault;
     std::unique_ptr<weld::Builder> m_xBuilder;
     std::unique_ptr<weld::Widget> m_xContainer;
     std::unique_ptr<weld::Label> m_xText;