Add scrollOffEnabled config

docs/Config.md

@@ -35,7 +35,8 @@ gui:
   windowSize: 'normal' # one of 'normal' | 'half' | 'full' default is 'normal'
   scrollHeight: 2 # how many lines you scroll by
   scrollPastBottom: true # enable scrolling past the bottom
-  scrollOffMargin: 2 # how many lines to keep before/after the cursor when it reaches the top/bottom of the view
+  scrollOffMargin: 2 # how many lines to keep before/after the cursor when it reaches the top/bottom of the view; see 'Scroll-off Margin' section below
+  scrollOffBehavior: 'margin' # one of 'margin' | 'jump'; see 'Scroll-off Margin' section below
   sidePanelWidth: 0.3333 # number from 0 to 1
   expandFocusedSidePanel: false
   mainPanelSplitMode: 'flexible' # one of 'horizontal' | 'flexible' | 'vertical'
@@ -349,6 +350,14 @@ or
 LG_CONFIG_FILE="$HOME/.base_lg_conf,$HOME/.light_theme_lg_conf" lazygit
 ```
 
+## Scroll-off Margin
+
+When the selected line gets close to the bottom of the window and you hit down-arrow, there's a feature called "scroll-off margin" that lets the view scroll a little earlier so that you can see a bit of what's coming in the direction that you are moving. This is controlled by the `gui.scrollOffMargin` setting (default: 2), so it keeps 2 lines below the selection visible as you scroll down. It can be set to 0 to scroll only when the selection reaches the bottom of the window.
+
+That's the behavior when `gui.scrollOffBehavior` is set to "margin" (the default). If you set `gui.scrollOffBehavior` to "jump", then upon reaching the last line of a view and hitting down-arrow the view will scroll by half a page so that the selection ends up in the middle of the view. This may feel a little jarring because the cursor jumps around when continuously moving down, but it has the advantage that the view doesn't scroll as often.
+
+This setting applies both to all list views (e.g. commits and branches etc), and to the staging view.
+
 ## Color Attributes
 
 For color attributes you can choose an array of attributes (with max one color attribute)

pkg/config/user_config.go

@@ -32,6 +32,7 @@ type GuiConfig struct {
 	ScrollHeight              int                `yaml:"scrollHeight"`
 	ScrollPastBottom          bool               `yaml:"scrollPastBottom"`
 	ScrollOffMargin           int                `yaml:"scrollOffMargin"`
+	ScrollOffBehavior         string             `yaml:"scrollOffBehavior"`
 	MouseEvents               bool               `yaml:"mouseEvents"`
 	SkipDiscardChangeWarning  bool               `yaml:"skipDiscardChangeWarning"`
 	SkipStashWarning          bool               `yaml:"skipStashWarning"`
@@ -420,6 +421,7 @@ func GetDefaultConfig() *UserConfig {
 			ScrollHeight:             2,
 			ScrollPastBottom:         true,
 			ScrollOffMargin:          2,
+			ScrollOffBehavior:        "margin",
 			MouseEvents:              true,
 			SkipDiscardChangeWarning: false,
 			SkipStashWarning:         false,

pkg/gui/controllers/scroll_off_margin.go

@@ -9,24 +9,28 @@ import (
 // To be called after pressing up-arrow; checks whether the cursor entered the
 // top scroll-off margin, and so the view needs to be scrolled up one line
 func checkScrollUp(view types.IViewTrait, userConfig *config.UserConfig, lineIdxBefore int, lineIdxAfter int) {
-	viewPortStart, viewPortHeight := view.ViewPortYBounds()
+	if userConfig.Gui.ScrollOffBehavior != "jump" {
+		viewPortStart, viewPortHeight := view.ViewPortYBounds()
 
-	linesToScroll := calculateLinesToScrollUp(
-		viewPortStart, viewPortHeight, userConfig.Gui.ScrollOffMargin, lineIdxBefore, lineIdxAfter)
-	if linesToScroll != 0 {
-		view.ScrollUp(linesToScroll)
+		linesToScroll := calculateLinesToScrollUp(
+			viewPortStart, viewPortHeight, userConfig.Gui.ScrollOffMargin, lineIdxBefore, lineIdxAfter)
+		if linesToScroll != 0 {
+			view.ScrollUp(linesToScroll)
+		}
 	}
 }
 
 // To be called after pressing down-arrow; checks whether the cursor entered the
 // bottom scroll-off margin, and so the view needs to be scrolled down one line
 func checkScrollDown(view types.IViewTrait, userConfig *config.UserConfig, lineIdxBefore int, lineIdxAfter int) {
-	viewPortStart, viewPortHeight := view.ViewPortYBounds()
+	if userConfig.Gui.ScrollOffBehavior != "jump" {
+		viewPortStart, viewPortHeight := view.ViewPortYBounds()
 
-	linesToScroll := calculateLinesToScrollDown(
-		viewPortStart, viewPortHeight, userConfig.Gui.ScrollOffMargin, lineIdxBefore, lineIdxAfter)
-	if linesToScroll != 0 {
-		view.ScrollDown(linesToScroll)
+		linesToScroll := calculateLinesToScrollDown(
+			viewPortStart, viewPortHeight, userConfig.Gui.ScrollOffMargin, lineIdxBefore, lineIdxAfter)
+		if linesToScroll != 0 {
+			view.ScrollDown(linesToScroll)
+		}
 	}
 }