Finish support for a fake cursor

internal/display/bufwindow.go

@@ -102,7 +102,7 @@ func (w *BufWindow) getStartInfo(n, lineN int) ([]byte, int, int, *tcell.Style)
 func (w *BufWindow) Clear() {
 	for y := 0; y < w.Height; y++ {
 		for x := 0; x < w.Width; x++ {
-			screen.Screen.SetContent(w.X+x, w.Y+y, ' ', nil, config.DefStyle)
+			screen.SetContent(w.X+x, w.Y+y, ' ', nil, config.DefStyle)
 		}
 	}
 }
@@ -298,9 +298,9 @@ func (w *BufWindow) drawGutter(vloc *buffer.Loc, bloc *buffer.Loc) {
 			break
 		}
 	}
-	screen.Screen.SetContent(w.X+vloc.X, w.Y+vloc.Y, char, nil, s)
+	screen.SetContent(w.X+vloc.X, w.Y+vloc.Y, char, nil, s)
 	vloc.X++
-	screen.Screen.SetContent(w.X+vloc.X, w.Y+vloc.Y, char, nil, s)
+	screen.SetContent(w.X+vloc.X, w.Y+vloc.Y, char, nil, s)
 	vloc.X++
 }
 
@@ -309,21 +309,21 @@ func (w *BufWindow) drawLineNum(lineNumStyle tcell.Style, softwrapped bool, maxL
 
 	// Write the spaces before the line number if necessary
 	for i := 0; i < maxLineNumLength-len(lineNum); i++ {
-		screen.Screen.SetContent(w.X+vloc.X, w.Y+vloc.Y, ' ', nil, lineNumStyle)
+		screen.SetContent(w.X+vloc.X, w.Y+vloc.Y, ' ', nil, lineNumStyle)
 		vloc.X++
 	}
 	// Write the actual line number
 	for _, ch := range lineNum {
 		if softwrapped {
-			screen.Screen.SetContent(w.X+vloc.X, w.Y+vloc.Y, ' ', nil, lineNumStyle)
+			screen.SetContent(w.X+vloc.X, w.Y+vloc.Y, ' ', nil, lineNumStyle)
 		} else {
-			screen.Screen.SetContent(w.X+vloc.X, w.Y+vloc.Y, ch, nil, lineNumStyle)
+			screen.SetContent(w.X+vloc.X, w.Y+vloc.Y, ch, nil, lineNumStyle)
 		}
 		vloc.X++
 	}
 
 	// Write the extra space
-	screen.Screen.SetContent(w.X+vloc.X, w.Y+vloc.Y, ' ', nil, lineNumStyle)
+	screen.SetContent(w.X+vloc.X, w.Y+vloc.Y, ' ', nil, lineNumStyle)
 	vloc.X++
 }
 
@@ -342,7 +342,7 @@ func (w *BufWindow) showCursor(x, y int, main bool) {
 		if main {
 			screen.ShowCursor(x, y)
 		} else {
-			screen.ShowFakeCursor(x, y)
+			screen.ShowFakeCursorMulti(x, y)
 		}
 	}
 }
@@ -513,7 +513,7 @@ func (w *BufWindow) displayBuffer() {
 					}
 				}
 
-				screen.Screen.SetContent(w.X+vloc.X, w.Y+vloc.Y, r, nil, style)
+				screen.SetContent(w.X+vloc.X, w.Y+vloc.Y, r, nil, style)
 
 				if showcursor {
 					for _, c := range cursors {
@@ -591,7 +591,7 @@ func (w *BufWindow) displayBuffer() {
 					curStyle = style.Background(fg)
 				}
 			}
-			screen.Screen.SetContent(i+w.X, vloc.Y+w.Y, ' ', nil, curStyle)
+			screen.SetContent(i+w.X, vloc.Y+w.Y, ' ', nil, curStyle)
 		}
 
 		draw(' ', curStyle, true)
@@ -617,7 +617,7 @@ func (w *BufWindow) displayStatusLine() {
 	} else if w.Y+w.Height != infoY {
 		w.drawStatus = true
 		for x := w.X; x < w.X+w.Width; x++ {
-			screen.Screen.SetContent(x, w.Y+w.Height-1, '-', nil, config.DefStyle.Reverse(true))
+			screen.SetContent(x, w.Y+w.Height-1, '-', nil, config.DefStyle.Reverse(true))
 		}
 	} else {
 		w.drawStatus = false
@@ -637,7 +637,7 @@ func (w *BufWindow) displayScrollBar() {
 		}
 		barstart := w.Y + int(float64(w.StartLine)/float64(w.Buf.LinesNum())*float64(w.Height))
 		for y := barstart; y < util.Min(barstart+barsize, w.Y+bufHeight); y++ {
-			screen.Screen.SetContent(scrollX, y, '|', nil, config.DefStyle.Reverse(true))
+			screen.SetContent(scrollX, y, '|', nil, config.DefStyle.Reverse(true))
 		}
 	}
 }

internal/display/infowindow.go

@@ -74,7 +74,7 @@ func (i *InfoWindow) LocFromVisual(vloc buffer.Loc) buffer.Loc {
 
 func (i *InfoWindow) Clear() {
 	for x := 0; x < i.Width; x++ {
-		screen.Screen.SetContent(x, i.Y, ' ', nil, i.defStyle())
+		screen.SetContent(x, i.Y, ' ', nil, i.defStyle())
 	}
 }
 
@@ -111,7 +111,7 @@ func (i *InfoWindow) displayBuffer() {
 				if j > 0 {
 					c = ' '
 				}
-				screen.Screen.SetContent(vlocX, i.Y, c, nil, style)
+				screen.SetContent(vlocX, i.Y, c, nil, style)
 			}
 			vlocX++
 		}
@@ -167,9 +167,9 @@ func (i *InfoWindow) displayKeyMenu() {
 	for y := 0; y < len(keydisplay); y++ {
 		for x := 0; x < i.Width; x++ {
 			if x < len(keydisplay[y]) {
-				screen.Screen.SetContent(x, i.Y-len(keydisplay)+y, rune(keydisplay[y][x]), nil, i.defStyle())
+				screen.SetContent(x, i.Y-len(keydisplay)+y, rune(keydisplay[y][x]), nil, i.defStyle())
 			} else {
-				screen.Screen.SetContent(x, i.Y-len(keydisplay)+y, ' ', nil, i.defStyle())
+				screen.SetContent(x, i.Y-len(keydisplay)+y, ' ', nil, i.defStyle())
 			}
 		}
 	}
@@ -194,7 +194,7 @@ func (i *InfoWindow) Display() {
 
 		display := i.Msg
 		for _, c := range display {
-			screen.Screen.SetContent(x, i.Y, c, nil, style)
+			screen.SetContent(x, i.Y, c, nil, style)
 			x += runewidth.RuneWidth(c)
 		}
 
@@ -219,13 +219,13 @@ func (i *InfoWindow) Display() {
 				style = style.Reverse(true)
 			}
 			for _, r := range s {
-				screen.Screen.SetContent(x, i.Y-keymenuOffset-1, r, nil, style)
+				screen.SetContent(x, i.Y-keymenuOffset-1, r, nil, style)
 				x++
 				if x >= i.Width {
 					return
 				}
 			}
-			screen.Screen.SetContent(x, i.Y-keymenuOffset-1, ' ', nil, statusLineStyle)
+			screen.SetContent(x, i.Y-keymenuOffset-1, ' ', nil, statusLineStyle)
 			x++
 			if x >= i.Width {
 				return
@@ -233,7 +233,7 @@ func (i *InfoWindow) Display() {
 		}
 
 		for x < i.Width {
-			screen.Screen.SetContent(x, i.Y-keymenuOffset-1, ' ', nil, statusLineStyle)
+			screen.SetContent(x, i.Y-keymenuOffset-1, ' ', nil, statusLineStyle)
 			x++
 		}
 	}

internal/display/statusline.go

@@ -118,13 +118,13 @@ func (s *StatusLine) Display() {
 				style = style.Reverse(true)
 			}
 			for _, r := range sug {
-				screen.Screen.SetContent(x, y-keymenuOffset, r, nil, style)
+				screen.SetContent(x, y-keymenuOffset, r, nil, style)
 				x++
 				if x >= s.win.Width {
 					return
 				}
 			}
-			screen.Screen.SetContent(x, y-keymenuOffset, ' ', nil, statusLineStyle)
+			screen.SetContent(x, y-keymenuOffset, ' ', nil, statusLineStyle)
 			x++
 			if x >= s.win.Width {
 				return
@@ -132,7 +132,7 @@ func (s *StatusLine) Display() {
 		}
 
 		for x < s.win.Width {
-			screen.Screen.SetContent(x, y-keymenuOffset, ' ', nil, statusLineStyle)
+			screen.SetContent(x, y-keymenuOffset, ' ', nil, statusLineStyle)
 			x++
 		}
 		return
@@ -184,7 +184,7 @@ func (s *StatusLine) Display() {
 					c = ' '
 					x++
 				}
-				screen.Screen.SetContent(winX+x, y, c, nil, statusLineStyle)
+				screen.SetContent(winX+x, y, c, nil, statusLineStyle)
 			}
 		} else if x >= s.win.Width-rightLen && x < rightLen+s.win.Width-rightLen {
 			r, size := utf8.DecodeRune(rightText)
@@ -196,10 +196,10 @@ func (s *StatusLine) Display() {
 					c = ' '
 					x++
 				}
-				screen.Screen.SetContent(winX+x, y, c, nil, statusLineStyle)
+				screen.SetContent(winX+x, y, c, nil, statusLineStyle)
 			}
 		} else {
-			screen.Screen.SetContent(winX+x, y, ' ', nil, statusLineStyle)
+			screen.SetContent(winX+x, y, ' ', nil, statusLineStyle)
 		}
 	}
 }

internal/display/tabwindow.go

@@ -91,13 +91,13 @@ func (w *TabWindow) Display() {
 					c = ' '
 				}
 				if x == w.width-1 && !done {
-					screen.Screen.SetContent(w.width-1, w.Y, '>', nil, config.DefStyle.Reverse(true))
+					screen.SetContent(w.width-1, w.Y, '>', nil, config.DefStyle.Reverse(true))
 					x++
 					break
 				} else if x == 0 && w.hscroll > 0 {
-					screen.Screen.SetContent(0, w.Y, '<', nil, config.DefStyle.Reverse(true))
+					screen.SetContent(0, w.Y, '<', nil, config.DefStyle.Reverse(true))
 				} else if x >= 0 && x < w.width {
-					screen.Screen.SetContent(x, w.Y, c, nil, config.DefStyle.Reverse(true))
+					screen.SetContent(x, w.Y, c, nil, config.DefStyle.Reverse(true))
 				}
 				x++
 			}

internal/display/termwindow.go

@@ -51,7 +51,7 @@ func (w *TermWindow) LocFromVisual(vloc buffer.Loc) buffer.Loc {
 func (w *TermWindow) Clear() {
 	for y := 0; y < w.Height; y++ {
 		for x := 0; x < w.Width; x++ {
-			screen.Screen.SetContent(w.X+x, w.Y+y, ' ', nil, config.DefStyle)
+			screen.SetContent(w.X+x, w.Y+y, ' ', nil, config.DefStyle)
 		}
 	}
 }
@@ -88,7 +88,7 @@ func (w *TermWindow) Display() {
 				st = st.Reverse(true)
 			}
 
-			screen.Screen.SetContent(w.X+x, w.Y+y, c, nil, st)
+			screen.SetContent(w.X+x, w.Y+y, c, nil, st)
 		}
 	}
 	if config.GetGlobalOption("statusline").(bool) {
@@ -103,9 +103,9 @@ func (w *TermWindow) Display() {
 			if x < textLen {
 				r, size := utf8.DecodeRune(text)
 				text = text[size:]
-				screen.Screen.SetContent(w.X+x, w.Y+w.Height, r, nil, statusLineStyle)
+				screen.SetContent(w.X+x, w.Y+w.Height, r, nil, statusLineStyle)
 			} else {
-				screen.Screen.SetContent(w.X+x, w.Y+w.Height, ' ', nil, statusLineStyle)
+				screen.SetContent(w.X+x, w.Y+w.Height, ' ', nil, statusLineStyle)
 			}
 		}
 	}

internal/display/uiwindow.go

@@ -28,7 +28,7 @@ func (w *UIWindow) drawNode(n *views.Node) {
 		if c.IsLeaf() && c.Kind == views.STVert {
 			if i != len(cs)-1 {
 				for h := 0; h < c.H; h++ {
-					screen.Screen.SetContent(c.X+c.W, c.Y+h, '|', nil, dividerStyle.Reverse(true))
+					screen.SetContent(c.X+c.W, c.Y+h, '|', nil, dividerStyle.Reverse(true))
 				}
 			}
 		} else {

internal/screen/screen.go

@@ -17,26 +17,66 @@ import (
 // screen. TODO: maybe we should worry about polling and drawing at the
 // same time too.
 var Screen tcell.Screen
+
+// The lock is necessary since the screen is polled on a separate thread
 var lock sync.Mutex
+
+// DrawChan is a channel that will cause the screen to redraw when
+// written to even if no event user event has occurred
 var DrawChan chan bool
 
+// Lock locks the screen lock
 func Lock() {
 	lock.Lock()
 }
 
+// Unlock unlocks the screen lock
 func Unlock() {
 	lock.Unlock()
 }
 
+// Redraw schedules a redraw with the draw channel
 func Redraw() {
 	DrawChan <- true
 }
 
+type screenCell struct {
+	x, y  int
+	r     rune
+	combc []rune
+	style tcell.Style
+}
+
+var lastCursor screenCell
+
+// ShowFakeCursor displays a cursor at the given position by modifying the
+// style of the given column instead of actually using the terminal cursor
+// This can be useful in certain terminals such as the windows console where
+// modifying the cursor location is slow and frequent modifications cause flashing
+// This keeps track of the most recent fake cursor location and resets it when
+// a new fake cursor location is specified
 func ShowFakeCursor(x, y int) {
+	r, combc, style, _ := Screen.GetContent(x, y)
+	Screen.SetContent(lastCursor.x, lastCursor.y, lastCursor.r, lastCursor.combc, lastCursor.style)
+	Screen.SetContent(x, y, r, combc, config.DefStyle.Reverse(true))
+
+	lastCursor.x, lastCursor.y = x, y
+	lastCursor.r = r
+	lastCursor.combc = combc
+	lastCursor.style = style
+}
+
+// ShowFakeCursorMulti is the same as ShowFakeCursor except it does not
+// reset previous locations of the cursor
+// Fake cursors are also necessary to display multiple cursors
+func ShowFakeCursorMulti(x, y int) {
 	r, _, _, _ := Screen.GetContent(x, y)
 	Screen.SetContent(x, y, r, nil, config.DefStyle.Reverse(true))
 }
 
+// ShowCursor puts the cursor at the given location using a fake cursor
+// if enabled or using the terminal cursor otherwise
+// By default only the windows console will use a fake cursor
 func ShowCursor(x, y int) {
 	if util.FakeCursor {
 		ShowFakeCursor(x, y)
@@ -45,6 +85,17 @@ func ShowCursor(x, y int) {
 	}
 }
 
+// SetContent sets a cell at a point on the screen and makes sure that it is
+// synced with the last cursor location
+func SetContent(x, y int, mainc rune, combc []rune, style tcell.Style) {
+	Screen.SetContent(x, y, mainc, combc, style)
+	if util.FakeCursor && lastCursor.x == x && lastCursor.y == y {
+		lastCursor.r = mainc
+		lastCursor.style = style
+		lastCursor.combc = combc
+	}
+}
+
 // TempFini shuts the screen down temporarily
 func TempFini() bool {
 	screenWasNil := Screen == nil

internal/util/util.go

@@ -33,7 +33,7 @@ var (
 	Debug = "ON"
 	// FakeCursor is used to disable the terminal cursor and have micro
 	// draw its own (enabled for windows consoles where the cursor is slow)
-	FakeCursor = true
+	FakeCursor = false
 )
 
 func init() {