Snapshot tests

.github/actions/run-tests/action.yml

@@ -1,8 +1,8 @@
 name: "Run tests"
-description: "Runs the specified tests using factos or core tests"
+description: "Runs the specified tests using ui or core tests"
 inputs:
-  use-factos:
-    description: 'Whether to use factos for test selection'
+  test-type:
+    description: 'The type of tests to run (factos, core or snapshot)'
     required: true
   id:
     description: "Identifier for the test target"
@@ -54,7 +54,7 @@ runs:
     # run tests using the factos selection and the console when no emulator is needed
     - name: Run UI tests
       uses: nick-fields/retry@v3.0.2
-      if : ${{ inputs.use-factos == 'true' && inputs.use-android-emulator != 'true' }}
+      if : ${{ inputs.test-type == 'factos' && inputs.use-android-emulator != 'true' }}
       with:
         timeout_minutes: 15
         max_attempts: 3
@@ -63,14 +63,14 @@ runs:
 
     # run tests using the factos selection inside the android emulator
     - name: Enable KVM
-      if : ${{ inputs.use-factos == 'true' && inputs.use-android-emulator == 'true' }}
+      if : ${{ inputs.test-type == 'factos' && inputs.use-android-emulator == 'true' }}
       shell: pwsh
       run: |
         echo 'KERNEL=="kvm", GROUP="kvm", MODE="0666", OPTIONS+="static_node=kvm"' | sudo tee /etc/udev/rules.d/99-kvm4all.rules
         sudo udevadm control --reload-rules
         sudo udevadm trigger --name-match=kvm
     - name: Create Test Script
-      if : ${{ inputs.use-factos == 'true' && inputs.use-android-emulator == 'true' }}
+      if : ${{ inputs.test-type == 'factos' && inputs.use-android-emulator == 'true' }}
       shell: bash
       run: |
         cat << 'EOF' > run_tests.sh
@@ -86,29 +86,39 @@ runs:
         EOF
         chmod +x run_tests.sh
     - name: Start Android emulator and run tests
-      if : ${{ inputs.use-factos == 'true' && inputs.use-android-emulator == 'true' }}
+      if : ${{ inputs.test-type == 'factos' && inputs.use-android-emulator == 'true' }}
       uses: reactivecircus/android-emulator-runner@v2.35.0
       with:
         api-level: 35
         target: google_apis
         arch: x86_64
         script: ./run_tests.sh
 
-    # run core tests when factos is not used
-    # the Debug config is required even we are testing the nuget packages in Release.
-    # this is because some optimizations in Release make the tests fail, but the code
-    # that fails is not related to the nuget packages but to the test code itself
-    # there is a function that mocks the ui drawing that fails in Release optimizations.
-    # ToDo: fix that, or now that we have ui tests, maybe just run the tests in the ui?.
-    - name: Run tests
+    - name: Run core tests
       uses: nick-fields/retry@v3.0.2
-      if : ${{ inputs.use-factos != 'true' }}
+      if : ${{ inputs.test-type == 'core' }}
       with:
         timeout_minutes: 8
         max_attempts: 3
         shell: pwsh
         command: dotnet run --project tests/CoreTests/CoreTests.csproj -c Debug -f ${{ inputs.target-framework }} --report-trx -p:UseNuGetPackages=true -p:LiveChartsVersionSuffix=-${{ github.sha }}
 
+    - name: Run snapshot tests
+      uses: nick-fields/retry@v3.0.2
+      if : ${{ inputs.test-type == 'snapshot' }}
+      with:
+        timeout_minutes: 8
+        max_attempts: 3
+        shell: pwsh
+        command: dotnet run --project tests/SnapshotTests/SnapshotTests.csproj -c Release --report-trx -p:UseNuGetPackages=true -p:LiveChartsVersionSuffix=-${{ github.sha }}
+
+    - name: Upload snapshot diffs
+      if: failure() && inputs.test-type == 'snapshot'
+      uses: actions/upload-artifact@v6.0.0
+      with:
+        name: snapshot-diffs
+        path: tests/SnapshotTests/bin/Release/net10.0/SnapshotsDiff/**/*
+
     - name: Upload test results
       if: always()
       uses: actions/upload-artifact@v6.0.0

.github/workflows/livecharts.yml

@@ -125,10 +125,27 @@ jobs:
         with:
           id: core
           test-id: core-${{ matrix.framework }}
-          use-factos: false
+          test-type: core
           target-framework: ${{ matrix.framework }}
           comment_id: ${{ needs.report-progress-starting.outputs.comment_id }}
 
+  test-snapshot:
+    runs-on: windows-2025
+    needs: [pack, report-progress-starting, collect-packages]
+    strategy:
+      fail-fast: false
+    steps:
+      - name: Checkout 
+        uses: actions/checkout@v6.0.1
+
+      - name: Run tests
+        uses: ./.github/actions/run-tests
+        with:
+          id: snapshot
+          test-id: snapshot
+          test-type: snapshot
+          comment_id: ${{ needs.report-progress-starting.outputs.comment_id }}
+
   test-windows:
     runs-on: windows-2025
     strategy:
@@ -163,7 +180,7 @@ jobs:
         uses: ./.github/actions/run-tests
         with:
           id: windows
-          use-factos: true
+          test-type: factos
           test-id: ${{ matrix.id }}
           workloads: ${{ matrix.workloads }}
           target-framework: ${{ matrix.tf }}
@@ -192,7 +209,7 @@ jobs:
         uses: ./.github/actions/run-tests
         with:
           id: linux
-          use-factos: true
+          test-type: factos
           test-id: ${{ matrix.id }}
           workloads: ${{ matrix.workloads }}
           target-framework: ${{ matrix.tf }}
@@ -221,7 +238,7 @@ jobs:
         uses: ./.github/actions/run-tests
         with:
           id: mac
-          use-factos: true
+          test-type: factos
           test-id: ${{ matrix.id }}
           workloads: ${{ matrix.workloads }}
           target-framework: ${{ matrix.tf }}
@@ -252,7 +269,7 @@ jobs:
         uses: ./.github/actions/run-tests
         with:
           id: browser
-          use-factos: true
+          test-type: factos
           test-id: ${{ matrix.id }}
           workloads: ${{ matrix.workloads }}
           target-framework: ${{ matrix.tf }}
@@ -282,7 +299,7 @@ jobs:
         uses: ./.github/actions/run-tests
         with:
           id: android
-          use-factos: true
+          test-type: factos
           test-id: ${{ matrix.id }}
           workloads: ${{ matrix.workloads }}
           target-framework: ${{ matrix.tf }}
@@ -313,7 +330,7 @@ jobs:
         uses: ./.github/actions/run-tests
         with:
           id: ios
-          use-factos: true
+          test-type: factos
           test-id: ${{ matrix.id }}
           workloads: ${{ matrix.workloads }}
           target-framework: ${{ matrix.tf }}
@@ -326,6 +343,7 @@ jobs:
     needs:
       - report-progress-starting
       - test-core
+      - test-snapshot
       - test-windows
       - test-linux
       - test-mac
@@ -356,7 +374,7 @@ jobs:
         with:
           comment_id: ${{ needs.report-progress-starting.outputs.comment_id }}
           content: |
-            core #${{ needs.test-core.result }}, windows #${{ needs.test-windows.result }}, linux #${{ needs.test-linux.result }}, mac #${{ needs.test-mac.result }}, browser #${{ needs.test-browser.result }}, android #${{ needs.test-android.result }}, ios #${{ needs.test-ios.result }}
+            Core #${{ needs.test-core.result }} | Snapshot #${{ needs.test-snapshot.result }} | Windows #${{ needs.test-windows.result }} | Linux #${{ needs.test-linux.result }} | Mac #${{ needs.test-mac.result }} | Browser #${{ needs.test-browser.result }} | Android #${{ needs.test-android.result }} | iOS #${{ needs.test-ios.result }}
 
             ### Test Results Summary (Passed) ✅ (4 / 4)
 
@@ -367,7 +385,7 @@ jobs:
           comment_id: ${{ needs.report-progress-starting.outputs.comment_id }}
           content: |
 
-            Core #${{ needs.test-core.result }} | Windows #${{ needs.test-windows.result }} | Linux #${{ needs.test-linux.result }} | Mac #${{ needs.test-mac.result }} | Browser #${{ needs.test-browser.result }} | Android #${{ needs.test-android.result }} | iOS #${{ needs.test-ios.result }}
+            Core #${{ needs.test-core.result }} | Snapshot #${{ needs.test-snapshot.result }} | Windows #${{ needs.test-windows.result }} | Linux #${{ needs.test-linux.result }} | Mac #${{ needs.test-mac.result }} | Browser #${{ needs.test-browser.result }} | Android #${{ needs.test-android.result }} | iOS #${{ needs.test-ios.result }}
 
             ### Test Results Summary (Failure) ❌ (4 / 4)
 

LiveCharts.slnx

@@ -158,6 +158,10 @@
       <BuildType Solution="AppStore|*" Project="Release" />
     </Project>
     <Project Path="tests/SharedUITests/SharedUITests.shproj" Id="730ba90c-a574-4b17-9eeb-c28a4d782449" />
+    <Project Path="tests/SnapshotTests/SnapshotTests.csproj" Id="12006a54-fa9e-4c2c-8e52-a53eb02cb45b">
+      <BuildType Solution="Ad-Hoc|*" Project="Release" />
+      <BuildType Solution="AppStore|*" Project="Release" />
+    </Project>
     <Project Path="tests/UITests/UITests.csproj" Id="78f0491c-c08c-406c-ae95-7af7ccdcfdca">
       <BuildType Solution="Ad-Hoc|*" Project="Release" />
       <BuildType Solution="AppStore|*" Project="Release" />

global.json

@@ -0,0 +1,5 @@
+{
+  "test": {
+    "runner": "Microsoft.Testing.Platform"
+  }
+}

src/LiveChartsCore/AssemblyInfo.cs

@@ -34,6 +34,7 @@
 #else
 
 [assembly: InternalsVisibleTo("CoreTests")]
+[assembly: InternalsVisibleTo("SnapshotTests")]
 [assembly: InternalsVisibleTo("LiveChartsCore.SkiaSharpView")]
 [assembly: InternalsVisibleTo("LiveChartsCore.Behaviours")]
 [assembly: InternalsVisibleTo("LiveChartsCore.SkiaSharpView.WinForms")]

src/LiveChartsCore/CartesianChartEngine.cs

@@ -756,7 +756,11 @@ protected internal override void Measure()
                 ce._isInternalSet = false;
             }
 
-            if (axis.IsVisible) AddVisual(axis.ChartElementSource);
+            if (axis.IsVisible)
+            {
+                AddVisual(axis.ChartElementSource);
+                axis.InvalidateCrosshair(this, _pointerPosition);
+            }
             axis.ChartElementSource.RemoveOldPaints(View); // <- this is probably obsolete.
             // the probable issue is the "IsVisible" property
         }

src/skiasharp/LiveChartsCore.SkiaSharp/Drawing/DrawingTextExtensions.cs

@@ -20,10 +20,7 @@
 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 // SOFTWARE.
 
-using System;
-using System.Collections.Generic;
 using System.Diagnostics;
-using System.Linq;
 using System.Text;
 using LiveChartsCore.Drawing;
 using LiveChartsCore.SkiaSharpView.Drawing.Geometries;
@@ -36,6 +33,7 @@ internal static class DrawingTextExtensions
 {
     internal static readonly PositionedBlob s_newLine = new(SKTextBlob.Create(string.Empty, new()), -1);
     private static readonly Dictionary<string, SKShaper> s_knownShapers = [];
+    private static readonly object s_lock = new();
 
     internal static void DrawLabel(this SKCanvas canvas, LabelGeometry label, float opacity = 1)
     {
@@ -288,10 +286,15 @@ private static PositionedBlob ShapeAndPlace(string text, SKFont font, SKPaint pa
             var typeface = font.Typeface ??
                 throw new Exception("A Typeface is required at this point.");
 
-            if (!s_knownShapers.TryGetValue(typeface.FamilyName, out var shaper))
+            SKShaper? shaper = null;
+
+            lock (s_lock)
             {
-                shaper = new SKShaper(typeface);
-                s_knownShapers[typeface.FamilyName] = shaper;
+                if (!s_knownShapers.TryGetValue(typeface.FamilyName, out shaper))
+                {
+                    shaper = new SKShaper(typeface);
+                    s_knownShapers[typeface.FamilyName] = shaper;
+                }
             }
 
             var result = shaper.Shape(text, paint);

src/skiasharp/LiveChartsCore.SkiaSharp/SKCharts/InMemorySkiaSharpChart.cs

@@ -55,7 +55,7 @@ static InMemorySkiaSharpChart()
     /// <value>
     /// The background.
     /// </value>
-    public SKColor Background { get; set; } = SKColors.White;
+    public SKColor Background { get; set; } = SKColors.Empty;
 
     /// <summary>
     /// Gets or sets the height.
@@ -151,7 +151,9 @@ public virtual void DrawOnCanvas(SKCanvas canvas)
         if (coreChart is null || coreChart is not Chart skiaChart)
             throw new Exception("Something is missing :(");
 
-        var bg = coreChart.GetTheme().VirtualBackroundColor.AsSKColor();
+        var bg = Background == SKColors.Empty
+            ? coreChart.GetTheme().VirtualBackroundColor.AsSKColor()
+            : Background;
 
         if (_drawnView is not null)
         {