Improve render performance (#3686)

- **PR Description**

Fix a performance regression that I introduced with v0.41: when entering
or leaving staging mode for a file, or when switching from a file that
has only unstaged changes to one that has both staged and unstaged
changes, there was a noticeable lag of about 500ms on my machine. With
the improvements in this PR we get this back down to about 20ms.

1 files changed, 26 insertions, 1 deletions

diff --git a/pkg/gui/controllers/screen_mode_actions.go b/pkg/gui/controllers/screen_mode_actions.go
index 1db27f2e2..2d0026793 100644
--- a/pkg/gui/controllers/screen_mode_actions.go
+++ b/pkg/gui/controllers/screen_mode_actions.go
@@ -1,6 +1,7 @@
 package controllers
 
 import (
+	"github.com/jesseduffield/gocui"
 	"github.com/jesseduffield/lazygit/pkg/gui/types"
 )
 
@@ -16,7 +17,7 @@ func (self *ScreenModeActions) Next() error {
 		),
 	)
 
-	return nil
+	return self.rerenderViewsWithScreenModeDependentContent()
 }
 
 func (self *ScreenModeActions) Prev() error {
@@ -27,9 +28,33 @@ func (self *ScreenModeActions) Prev() error {
 		),
 	)
 
+	return self.rerenderViewsWithScreenModeDependentContent()
+}
+
+// these views need to be re-rendered when the screen mode changes. The commits view,
+// for example, will show authorship information in half and full screen mode.
+func (self *ScreenModeActions) rerenderViewsWithScreenModeDependentContent() error {
+	for _, context := range self.c.Context().AllList() {
+		if context.NeedsRerenderOnWidthChange() == types.NEEDS_RERENDER_ON_WIDTH_CHANGE_WHEN_SCREEN_MODE_CHANGES {
+			if err := self.rerenderView(context.GetView()); err != nil {
+				return err
+			}
+		}
+	}
+
 	return nil
 }
 
+func (self *ScreenModeActions) rerenderView(view *gocui.View) error {
+	context, ok := self.c.Helpers().View.ContextForView(view.Name())
+	if !ok {
+		self.c.Log.Errorf("no context found for view %s", view.Name())
+		return nil
+	}
+
+	return context.HandleRender()
+}
+
 func nextIntInCycle(sl []types.WindowMaximisation, current types.WindowMaximisation) types.WindowMaximisation {
 	for i, val := range sl {
 		if val == current {