Blame: Display author avatar and a recency marker in the gutter

+ add a setting to disable it

Note: Height estimation (proposed in gitextensions#6605 (comment) )

+ Use greenish colors for heatmap with color adaptation for other themes

Color chosen from: https://colorbrewer2.org/#type=sequential&scheme=Greens&n=9

GitCommands/Settings/AppSettings.cs

@@ -1689,6 +1689,12 @@ public static bool BlameShowOriginalFilePath
             set => SetBool("Blame.ShowOriginalFilePath", value);
         }
 
+        public static bool BlameShowAuthorAvatar
+        {
+            get => GetBool("Blame.ShowAuthorAvatar", true);
+            set => SetBool("Blame.ShowAuthorAvatar", value);
+        }
+
         public static bool IsPortable()
         {
             return Properties.Settings.Default.IsPortable;

GitUI/Avatars/AvatarService.cs

@@ -4,7 +4,7 @@ namespace GitUI.Avatars
 {
     public static class AvatarService
     {
-        private static InitialsAvatarGenerator AvatarGenerator = new InitialsAvatarGenerator();
+        private static readonly InitialsAvatarGenerator AvatarGenerator = new InitialsAvatarGenerator();
         public static IAvatarProvider Default { get; }
             = new BackupAvatarProvider(new AvatarMemoryCache(new AvatarPersistentCache(new AvatarDownloader(AvatarGenerator), AvatarGenerator)),
                 Images.User80);

GitUI/CommandsDialogs/FormFileHistory.cs

@@ -135,6 +135,7 @@ public FormFileHistory(GitUICommands commands, string fileName, GitRevision revi
                 detectMoveAndCopyInAllFilesToolStripMenuItem.Checked = AppSettings.DetectCopyInAllOnBlame;
                 detectMoveAndCopyInThisFileToolStripMenuItem.Checked = AppSettings.DetectCopyInFileOnBlame;
                 displayAuthorFirstToolStripMenuItem.Checked = AppSettings.BlameDisplayAuthorFirst;
+                showAuthorAvatarToolStripMenuItem.Checked = AppSettings.BlameShowAuthorAvatar;
                 showAuthorToolStripMenuItem.Checked = AppSettings.BlameShowAuthor;
                 showAuthorDateToolStripMenuItem.Checked = AppSettings.BlameShowAuthorDate;
                 showAuthorTimeToolStripMenuItem.Checked = AppSettings.BlameShowAuthorTime;
@@ -704,5 +705,12 @@ private void showOriginalFilePathToolStripMenuItem_Click(object sender, EventArg
             showOriginalFilePathToolStripMenuItem.Checked = AppSettings.BlameShowOriginalFilePath;
             UpdateSelectedFileViewers(true);
         }
+
+        private void showAuthorAvatarToolStripMenuItem_Click(object sender, EventArgs e)
+        {
+            AppSettings.BlameShowAuthorAvatar = !AppSettings.BlameShowAuthorAvatar;
+            showAuthorAvatarToolStripMenuItem.Checked = AppSettings.BlameShowAuthorAvatar;
+            UpdateSelectedFileViewers(true);
+        }
     }
 }

GitUI/Editor/BlameAuthorMargin.cs

@@ -0,0 +1,110 @@
+using System;
+using System.Collections.Generic;
+using System.Drawing;
+using System.Linq;
+using System.Windows.Forms;
+using GitExtUtils.GitUI;
+using ICSharpCode.TextEditor;
+
+namespace GitUI.Editor
+{
+    /// <summary>
+    /// This class display avatars in the gutter in a blame control.
+    /// </summary>
+    public class BlameAuthorMargin : AbstractMargin
+    {
+        private static readonly int RecencyIndexWidth = Convert.ToInt32(4 * DpiUtil.ScaleX);
+        private List<Image> _avatars;
+        private readonly int _lineHeight;
+        private readonly Color _backgroundColor;
+        private List<GitBlameEntry> _blameLines;
+        private readonly Dictionary<int, SolidBrush> _brushs = new Dictionary<int, SolidBrush>();
+        private bool _isVisible = true;
+
+        public BlameAuthorMargin(TextArea textArea) : base(textArea)
+        {
+            _lineHeight = GetFontHeight(textArea.Font);
+            _backgroundColor = SystemColors.Window;
+            Width = _lineHeight + RecencyIndexWidth + DpiUtil.Scale(2);
+        }
+
+        public override int Width { get; }
+        public override bool IsVisible => _isVisible;
+
+        private static int GetFontHeight(Font font)
+        {
+            var max = Math.Max(
+                TextRenderer.MeasureText("_", font).Height,
+                (int)Math.Ceiling(font.GetHeight()));
+
+            return max + 1;
+        }
+
+        public void Initialize(List<GitBlameEntry> blameLines)
+        {
+            _blameLines = blameLines;
+            _avatars = blameLines.Select(a => a.Avatar).ToList();
+
+            // Update the resolution otherwise the image is not drawn at the good size :(
+            foreach (var avatar in _avatars)
+            {
+                if (avatar is Bitmap bitmapAvatar)
+                {
+                    bitmapAvatar.SetResolution(DpiUtil.DpiX, DpiUtil.DpiY);
+                }
+            }
+
+            // Build brushes
+            foreach (var blameLine in blameLines)
+            {
+                if (!_brushs.ContainsKey(blameLine.AgeBucketIndex))
+                {
+                    _brushs.Add(blameLine.AgeBucketIndex, new SolidBrush(blameLine.AgeBucketColor));
+                }
+            }
+        }
+
+        public void SetVisiblity(bool isVisible)
+        {
+            _isVisible = isVisible;
+        }
+
+        public override void Paint(Graphics g, Rectangle rect)
+        {
+            if (rect.Width <= 0 || rect.Height <= 0)
+            {
+                return;
+            }
+
+            g.Clear(_backgroundColor);
+
+            if (_avatars == null || _avatars.Count == 0)
+            {
+                return;
+            }
+
+            var verticalOffset = textArea.VirtualTop.Y;
+            var lineStart = verticalOffset / _lineHeight;
+            var negativeOffset = (lineStart * _lineHeight) - verticalOffset;
+            var lineCount = (int)Math.Ceiling((double)(rect.Height - negativeOffset) / _lineHeight);
+
+            for (int i = 0; i < lineCount; i++)
+            {
+                if (lineStart + i >= _avatars.Count)
+                {
+                    break;
+                }
+
+                int y = negativeOffset + (i * _lineHeight);
+                g.FillRectangle(_brushs[_blameLines[lineStart + i].AgeBucketIndex], 0, y, RecencyIndexWidth, _lineHeight);
+
+                if (_avatars[lineStart + i] != null)
+                {
+                    g.DrawImage(_avatars[lineStart + i], new Point(RecencyIndexWidth, y));
+                }
+            }
+
+            base.Paint(g, rect);
+        }
+    }
+}

GitUI/Editor/FileViewer.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.ComponentModel;
 using System.Drawing;
 using System.IO;
@@ -1618,5 +1619,15 @@ public bool ShowSyntaxHighlightingInDiff
             public ToolStripButton IgnoreAllWhitespacesButton => _fileViewer.ignoreAllWhitespaces;
             public ToolStripMenuItem IgnoreAllWhitespacesMenuItem => _fileViewer.ignoreAllWhitespaceChangesToolStripMenuItem;
         }
+
+        public void SetGitBlameGutter(List<GitBlameEntry> gitBlameEntries)
+        {
+            internalFileViewer.ShowGutterAvatars = AppSettings.BlameShowAuthorAvatar;
+
+            if (AppSettings.BlameShowAuthorAvatar)
+            {
+                internalFileViewer.SetGitBlameGutter(gitBlameEntries);
+            }
+        }
     }
 }

GitUI/Editor/FileViewerInternal.cs

@@ -33,6 +33,8 @@ public partial class FileViewerInternal : GitModuleControl, IFileViewer
         private readonly CurrentViewPositionCache _currentViewPositionCache;
         private DiffViewerLineNumberControl _lineNumbersControl;
         private DiffHighlightService _diffHighlightService = DiffHighlightService.Instance;
+        private BlameAuthorMargin _authorsAvatarMargin;
+        private bool _showGutterAvatars;
 
         public FileViewerInternal()
         {
@@ -487,6 +489,39 @@ private void OnVScrollPositionChanged(EventArgs e)
 
         #endregion
 
+        public void SetGitBlameGutter(List<GitBlameEntry> gitBlameEntries)
+        {
+            if (_showGutterAvatars)
+            {
+                _authorsAvatarMargin.Initialize(gitBlameEntries);
+            }
+        }
+
+        public bool ShowGutterAvatars
+        {
+            get => _showGutterAvatars;
+            set
+            {
+                _showGutterAvatars = value;
+                if (!_showGutterAvatars)
+                {
+                    _authorsAvatarMargin?.SetVisiblity(false);
+
+                    return;
+                }
+
+                if (_authorsAvatarMargin == null)
+                {
+                    _authorsAvatarMargin = new BlameAuthorMargin(TextEditor.ActiveTextAreaControl.TextArea);
+                    TextEditor.ActiveTextAreaControl.TextArea.InsertLeftMargin(0, _authorsAvatarMargin);
+                }
+                else
+                {
+                    _authorsAvatarMargin.SetVisiblity(true);
+                }
+            }
+        }
+
         internal sealed class CurrentViewPositionCache
         {
             private readonly FileViewerInternal _viewer;

GitUI/Editor/GitBlameEntry.cs

@@ -0,0 +1,11 @@
+using System.Drawing;
+
+namespace GitUI.Editor
+{
+    public class GitBlameEntry
+    {
+        public Image Avatar { get; set; }
+        public int AgeBucketIndex { get; set; }
+        public Color AgeBucketColor { get; set; }
+    }
+}

GitUI/Translation/English.xlf

@@ -4288,6 +4288,10 @@ If you are not sure just close this window.</source>
         <source>Save as</source>
         <target />
       </trans-unit>
+      <trans-unit id="showAuthorAvatarToolStripMenuItem.Text">
+        <source>Show author avatar</source>
+        <target />
+      </trans-unit>
       <trans-unit id="showAuthorDateToolStripMenuItem.Text">
         <source>Show author date</source>
         <target />