icons: Implement the fallback mechanism for icons.

When an icon is not found in eg. images_sifr.zip, search it in
images_tango.zip, etc.

Change-Id: I8af952a1bd8e9e02531f84012e8ce39e75422313

2 files changed, 37 insertions, 10 deletions

diff --git a/vcl/inc/impimagetree.hxx b/vcl/inc/impimagetree.hxx
index 7e8dda75ea7a..e66e754a1c8d 100644
--- a/vcl/inc/impimagetree.hxx
+++ b/vcl/inc/impimagetree.hxx
@@ -95,8 +95,17 @@ private:
     bool findImage(std::vector< OUString > const & paths, BitmapEx & bitmap );
 
     void loadImageLinks();
+
     void parseLinkFile(boost::shared_ptr< SvStream > stream);
+
+    /// Return name of a real .png according to links.txt.
     OUString const & getRealImageName(OUString const & name);
+
+    /** Rerurn name of the fallback style for the provided one.
+
+        Must not be cyclic :-)  The last theme in the chain returns an empty string.
+    */
+    OUString fallbackStyle(const OUString &style);
 };
 
 typedef salhelper::SingletonRef< ImplImageTree > ImplImageTreeSingletonRef;
diff --git a/vcl/source/gdi/impimagetree.cxx b/vcl/source/gdi/impimagetree.cxx
index 9ce7fd2e6053..8955902039fe 100644
--- a/vcl/source/gdi/impimagetree.cxx
+++ b/vcl/source/gdi/impimagetree.cxx
@@ -101,21 +101,39 @@ ImplImageTree::~ImplImageTree()
 {
 }
 
+OUString ImplImageTree::fallbackStyle(const OUString &style)
+{
+    if (style == "galaxy")
+        return OUString();
+    else if (style == "industrial")
+        return OUString("galaxy");
+    else if (style == "tango")
+        return OUString("industrial");
+    else if (style == "breeze")
+        return OUString("sifr");
+
+    return OUString("tango");
+}
+
 bool ImplImageTree::loadImage(OUString const & name, OUString const & style, BitmapEx & bitmap,
     bool localized, bool loadMissing)
 {
-    bool found = false;
-    try {
-        found = doLoadImage(name, style, bitmap, localized);
-    } catch (css::uno::RuntimeException &) {
-        if (!loadMissing)
-            throw;
+    OUString aStyle(style);
+    while (!aStyle.isEmpty())
+    {
+        try {
+            if (doLoadImage(name, aStyle, bitmap, localized))
+                return true;
+        }
+        catch (css::uno::RuntimeException &) {}
+
+        aStyle = fallbackStyle(aStyle);
     }
-    if (found || !loadMissing)
-        return found;
 
-    SAL_INFO("vcl", "ImplImageTree::loadImage exception couldn't load \""
-        << name << "\", fetching default image");
+    if (!loadMissing)
+        return false;
+
+    SAL_INFO("vcl", "ImplImageTree::loadImage couldn't load \"" << name << "\", fetching default image");
 
     return loadDefaultImage(style, bitmap);
 }