Make sure the inverted cursor is always readable (microsoft#3647)

alabuzhev · Aug 15, 2022 · deeaff8 · deeaff8
1 parent 1b3d004
commit deeaff8
Show file tree

Hide file tree

Showing 4 changed files with 12 additions and 3 deletions.
diff --git a/.github/actions/spelling/allow/apis.txt b/.github/actions/spelling/allow/apis.txt
@@ -103,6 +103,7 @@ lround
 Lsa
 lsass
 LSHIFT
+LTGRAY
 MAINWINDOW
 memchr
 memicmp
@@ -146,6 +147,7 @@ OUTLINETEXTMETRICW
 overridable
 PACL
 PAGESCROLL
+PATINVERT
 PEXPLICIT
 PICKFOLDERS
 pmr

diff --git a/src/renderer/atlas/shader_ps.hlsl b/src/renderer/atlas/shader_ps.hlsl
@@ -183,6 +183,9 @@ float4 main(float4 pos: SV_Position): SV_Target
         [flatten] if (cursorColor == INVALID_COLOR && glyphs[cellPos].a != 0)
         {
             color = float4(1 - color.rgb, 1);
+
+            // Make sure the cursor is always readable (see gh-3647)
+            color = float4((((uint3(color.rgb * 255) ^ 0x3f) & 0xff) / 255.0).rgb, 1);
         }
     }
 

diff --git a/src/renderer/dx/CustomTextRenderer.cpp b/src/renderer/dx/CustomTextRenderer.cpp
@@ -395,8 +395,8 @@ try
         if (firstPass)
         {
             // Draw a backplate behind the cursor in the *background* color so that we can invert it later.
-            // We're going to draw the exact same color as the background behind the cursor
-            const til::color color{ drawingContext.backgroundBrush->GetColor() };
+            // Make sure the cursor is always readable (see gh-3647)
+            const til::color color{ til::color{ drawingContext.backgroundBrush->GetColor() } ^ RGB(63, 63, 63) };
             RETURN_IF_FAILED(d2dContext->CreateSolidColorBrush(color.with_alpha(255),
                                                                &brush));
         }

diff --git a/src/renderer/gdi/paint.cpp b/src/renderer/gdi/paint.cpp
@@ -733,7 +733,11 @@ bool GdiEngine::FontHasWesternScript(HDC hdc)
 
         for (auto r : cursorInvertRects)
         {
-            RETURN_HR_IF(E_FAIL, !(InvertRect(_hdcMemoryContext, &r)));
+            // Make sure the cursor is always readable (see gh-3647)
+            const auto PrevObject = SelectObject(_hdcMemoryContext, GetStockObject(LTGRAY_BRUSH));
+            const auto Result = PatBlt(_hdcMemoryContext, r.left, r.top, r.right - r.left, r.bottom - r.top, PATINVERT);
+            SelectObject(_hdcMemoryContext, PrevObject);
+            RETURN_HR_IF(E_FAIL, !Result);
         }
     }