Release v0.6.20: edit history images and share smooth wheel handling

tests/tests.cpp

@@ -1,4 +1,5 @@
 #include "autocorrect.h"
+#include "history_preview.h"
 #include "ocr.h"
 #include "richtext.h"
 #include "storage.h"
@@ -22,6 +23,20 @@ void rejects(const std::function<void()> &f, const char *name)
     bool thrown = false;
     try
     {
+        {
+            std::map<std::wstring,int> previews;
+            std::set<std::wstring> visible;
+            for(int i=0;i<40;++i) previews[std::to_wstring(i)]=i;
+            for(int i=0;i<8;++i) visible.insert(std::to_wstring(i));
+            ks::trimHistoryPreviews(previews,visible);
+            require(previews.size()==32,"preview cache stays bounded");
+            for(const auto &id:visible) require(previews.contains(id),"visible preview survives eviction");
+            for(int i=0;i<40;++i) { auto id=std::to_wstring(i); previews[id]=i; visible.insert(id); }
+            ks::trimHistoryPreviews(previews,visible);
+            require(previews.size()==40,"tall viewport does not thrash visible previews");
+            visible.clear(); ks::trimHistoryPreviews(previews,visible);
+            require(previews.size()==32,"cache shrinks after leaving tall viewport");
+        }
         f();
     }
     catch (...)