Scroll partial pages

docs/Config.md

@@ -52,7 +52,7 @@ gui:
     # Map of file extensions (including the dot) to icon properties (icon and color)
     extensions: {}
 
-  # The number of lines you scroll by when scrolling the main window
+  # The number of lines you scroll by when scrolling the main window. When using a number between 0 and 1, scrools that percentag of a whole page.
   scrollHeight: 2
 
   # If true, allow scrolling past the bottom of the content in the main window

pkg/config/user_config.go

@@ -60,8 +60,8 @@ type GuiConfig struct {
 	// Custom icons for filenames and file extensions
 	// See https://github.com/jesseduffield/lazygit/blob/master/docs/Config.md#custom-files-icon--color
 	CustomIcons CustomIconsConfig `yaml:"customIcons"`
-	// The number of lines you scroll by when scrolling the main window
-	ScrollHeight int `yaml:"scrollHeight" jsonschema:"minimum=1"`
+	// The number of lines you scroll by when scrolling the main window. When using a number between 0 and 1, scrools that percentag of a whole page.
+	ScrollHeight float64 `yaml:"scrollHeight" jsonschema:"minimum=0.01"`
 	// If true, allow scrolling past the bottom of the content in the main window
 	ScrollPastBottom bool `yaml:"scrollPastBottom"`
 	// See https://github.com/jesseduffield/lazygit/blob/master/docs/Config.md#scroll-off-margin

pkg/gui/controllers/list_controller.go

@@ -3,6 +3,7 @@ package controllers
 import (
 	"github.com/jesseduffield/gocui"
 	"github.com/jesseduffield/lazygit/pkg/gui/types"
+	"github.com/jesseduffield/lazygit/pkg/utils"
 )
 
 type ListControllerFactory struct {
@@ -51,7 +52,8 @@ func (self *ListController) HandleScrollRight() error {
 }
 
 func (self *ListController) HandleScrollUp() error {
-	scrollHeight := self.c.UserConfig().Gui.ScrollHeight
+	var _, windowHeight int = self.context.GetViewTrait().ViewPortYBounds()
+	scrollHeight := utils.ScrollHeight(windowHeight, self.c.UserConfig().Gui.ScrollHeight)
 	self.context.GetViewTrait().ScrollUp(scrollHeight)
 	if self.context.RenderOnlyVisibleLines() {
 		self.context.HandleRender()
@@ -61,7 +63,8 @@ func (self *ListController) HandleScrollUp() error {
 }
 
 func (self *ListController) HandleScrollDown() error {
-	scrollHeight := self.c.UserConfig().Gui.ScrollHeight
+	var _, windowHeight int = self.context.GetViewTrait().ViewPortYBounds()
+	scrollHeight := utils.ScrollHeight(windowHeight, self.c.UserConfig().Gui.ScrollHeight)
 	self.context.GetViewTrait().ScrollDown(scrollHeight)
 	if self.context.RenderOnlyVisibleLines() {
 		self.context.HandleRender()

pkg/gui/controllers/merge_conflicts_controller.go

@@ -7,6 +7,7 @@ import (
 	"github.com/jesseduffield/lazygit/pkg/gui/context"
 	"github.com/jesseduffield/lazygit/pkg/gui/mergeconflicts"
 	"github.com/jesseduffield/lazygit/pkg/gui/types"
+	"github.com/jesseduffield/lazygit/pkg/utils"
 )
 
 type MergeConflictsController struct {
@@ -167,14 +168,16 @@ func (self *MergeConflictsController) GetOnFocusLost() func(types.OnFocusLostOpt
 
 func (self *MergeConflictsController) HandleScrollUp() error {
 	self.context().SetUserScrolling(true)
-	self.context().GetViewTrait().ScrollUp(self.c.UserConfig().Gui.ScrollHeight)
+	_, windowHeight := self.context().GetViewTrait().ViewPortYBounds()
+	self.context().GetViewTrait().ScrollUp(utils.ScrollHeight(windowHeight, self.c.UserConfig().Gui.ScrollHeight))
 
 	return nil
 }
 
 func (self *MergeConflictsController) HandleScrollDown() error {
 	self.context().SetUserScrolling(true)
-	self.context().GetViewTrait().ScrollDown(self.c.UserConfig().Gui.ScrollHeight)
+	_, windowHeight := self.context().GetViewTrait().ViewPortYBounds()
+	self.context().GetViewTrait().ScrollDown(utils.ScrollHeight(windowHeight, self.c.UserConfig().Gui.ScrollHeight))
 
 	return nil
 }

pkg/gui/controllers/vertical_scroll_controller.go

@@ -3,6 +3,7 @@ package controllers
 import (
 	"github.com/jesseduffield/gocui"
 	"github.com/jesseduffield/lazygit/pkg/gui/types"
+	"github.com/jesseduffield/lazygit/pkg/utils"
 )
 
 // given we have no fields here, arguably we shouldn't even need this factory
@@ -60,13 +61,16 @@ func (self *VerticalScrollController) GetMouseKeybindings(opts types.Keybindings
 }
 
 func (self *VerticalScrollController) HandleScrollUp() error {
-	self.context.GetViewTrait().ScrollUp(self.c.UserConfig().Gui.ScrollHeight)
+	heightInLines := self.context.GetView().Height()
+	scrollHeight := self.c.UserConfig().Gui.ScrollHeight
+	self.context.GetViewTrait().ScrollUp(utils.ScrollHeight(heightInLines, scrollHeight))
 
 	return nil
 }
 
 func (self *VerticalScrollController) HandleScrollDown() error {
-	scrollHeight := self.c.UserConfig().Gui.ScrollHeight
+	heightInLines := self.context.GetView().Height()
+	scrollHeight := utils.ScrollHeight(heightInLines, self.c.UserConfig().Gui.ScrollHeight)
 	self.context.GetViewTrait().ScrollDown(scrollHeight)
 
 	if manager := self.c.GetViewBufferManagerForView(self.context.GetView()); manager != nil {

pkg/gui/global_handlers.go

@@ -13,11 +13,11 @@ import (
 const HORIZONTAL_SCROLL_FACTOR = 3
 
 func (gui *Gui) scrollUpView(view *gocui.View) {
-	view.ScrollUp(gui.c.UserConfig().Gui.ScrollHeight)
+	view.ScrollUp(utils.ScrollHeight(view.Height(), gui.c.UserConfig().Gui.ScrollHeight))
 }
 
 func (gui *Gui) scrollDownView(view *gocui.View) {
-	scrollHeight := gui.c.UserConfig().Gui.ScrollHeight
+	scrollHeight := utils.ScrollHeight(view.Height(), gui.c.UserConfig().Gui.ScrollHeight)
 	view.ScrollDown(scrollHeight)
 
 	if manager := gui.getViewBufferManagerForView(view); manager != nil {

pkg/utils/scroll_lines.go

@@ -0,0 +1,24 @@
+package utils
+
+import "math"
+
+// The configuration option for scrollheight uses partial pages when it is
+// between (-1,1). This function calculates the scroll height based based of
+// the window height.
+func ScrollHeight(windowHeight int, scrollHeight float64) int {
+	if scrollHeight == 0 || windowHeight <= 0 {
+		// non-sensical value
+		return 2
+	} else if math.Abs(scrollHeight) <= 1 {
+		// scroll partial pages
+		var linesToScroll float64 = math.RoundToEven(math.Abs(scrollHeight) * float64(windowHeight))
+		linesToScroll = math.Max(1, linesToScroll)
+		if scrollHeight < 0 {
+			return -1 * int(linesToScroll)
+		} else {
+			return int(linesToScroll)
+		}
+	} else {
+		return int(math.Round(scrollHeight))
+	}
+}

pkg/utils/scroll_lines_test.go

@@ -0,0 +1,67 @@
+package utils
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestScrollHeight(t *testing.T) {
+	type scenario struct {
+		windowHeight           int
+		scrollHeightFromConfig float64
+		expected               int
+	}
+
+	scenarios := []scenario{
+		{
+			10,
+			5,
+			5,
+		},
+		{
+			1000,
+			-5,
+			-5,
+		},
+		{
+			10,
+			-5.2,
+			-5,
+		},
+		{
+			10,
+			0.5,
+			5,
+		},
+		{
+			12,
+			-0.25,
+			-3,
+		},
+		{
+			9,
+			0.5,
+			4,
+		},
+		{
+			9,
+			-0.5,
+			-4,
+		},
+		{
+			1,
+			-0.5,
+			-1,
+		},
+		{
+			1,
+			0.5,
+			1,
+		},
+	}
+
+	for _, s := range scenarios {
+		assert.EqualValues(t, s.expected, ScrollHeight(s.windowHeight, s.scrollHeightFromConfig))
+	}
+}

schema/config.json

@@ -437,9 +437,9 @@
           "description": "Custom icons for filenames and file extensions\nSee https://github.com/jesseduffield/lazygit/blob/master/docs/Config.md#custom-files-icon--color"
         },
         "scrollHeight": {
-          "type": "integer",
-          "minimum": 1,
-          "description": "The number of lines you scroll by when scrolling the main window",
+          "type": "number",
+          "minimum": 0.01,
+          "description": "The number of lines you scroll by when scrolling the main window. When using a number between 0 and 1, scrools that percentag of a whole page.",
           "default": 2
         },
         "scrollPastBottom": {