From 2c5888e25a0a06c8215ff56de8cb3227f529482c Mon Sep 17 00:00:00 2001
From: Nathan Sobo <nathan@github.com>
Date: Wed, 21 Jan 2015 16:47:03 -0700
Subject: [PATCH] Add ::state.content.scrollHeight to TextEditorPresenter

---
 spec/text-editor-presenter-spec.coffee | 15 +++++++++++++++
 src/text-editor-presenter.coffee       | 12 ++++++++----
 2 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/spec/text-editor-presenter-spec.coffee b/spec/text-editor-presenter-spec.coffee
index a0023bce7..3dffc19e3 100644
--- a/spec/text-editor-presenter-spec.coffee
+++ b/spec/text-editor-presenter-spec.coffee
@@ -67,6 +67,21 @@ describe "TextEditorPresenter", ->
           editor.setSoftWrapped(false)
           expect(presenter.state.content.scrollWidth).toBe 10 * editor.getMaxScreenLineLength() + 1
 
+      describe ".scrollHeight", ->
+        it "is initialized based on the lineHeight and the number of lines", ->
+          presenter = new TextEditorPresenter(model: editor, scrollTop: 0, lineHeight: 10, lineOverdrawMargin: 1)
+          expect(presenter.state.content.scrollHeight).toBe editor.getScreenLineCount() * 10
+
+        it "updates when the ::lineHeight changes", ->
+          presenter = new TextEditorPresenter(model: editor, scrollTop: 0, lineHeight: 10, lineOverdrawMargin: 1)
+          presenter.setLineHeight(20)
+          expect(presenter.state.content.scrollHeight).toBe editor.getScreenLineCount() * 20
+
+        it "updates when the line count changes", ->
+          presenter = new TextEditorPresenter(model: editor, scrollTop: 0, lineHeight: 10, lineOverdrawMargin: 1)
+          editor.getBuffer().append("\n\n\n")
+          expect(presenter.state.content.scrollHeight).toBe editor.getScreenLineCount() * 10
+
       describe ".indentGuidesVisible", ->
         it "is initialized based on the editor.showIndentGuide config setting", ->
           presenter = new TextEditorPresenter(model: editor)
diff --git a/src/text-editor-presenter.coffee b/src/text-editor-presenter.coffee
index 33975e299..a46c4ac45 100644
--- a/src/text-editor-presenter.coffee
+++ b/src/text-editor-presenter.coffee
@@ -14,7 +14,7 @@ class TextEditorPresenter
     @disposables.dispose()
 
   observeModel: ->
-    @disposables.add @model.onDidChange(@updateLinesState.bind(this))
+    @disposables.add @model.onDidChange(@updateState.bind(this))
     @disposables.add @model.onDidChangeSoftWrapped(@updateState.bind(this))
     @disposables.add @model.onDidChangeGrammar(@updateContentState.bind(this))
     @disposables.add @model.onDidAddDecoration(@didAddDecoration.bind(this))
@@ -30,9 +30,8 @@ class TextEditorPresenter
     @buildLinesState()
 
   buildContentState: ->
-    @state.content =
-      scrollWidth: @computeScrollWidth()
-      indentGuidesVisible: atom.config.get('editor.showIndentGuide', scope: @model.getRootScopeDescriptor())
+    @state.content = {}
+    @updateContentState()
 
   buildLinesState: ->
     @state.content.lines = {}
@@ -44,6 +43,7 @@ class TextEditorPresenter
 
   updateContentState: ->
     @state.content.scrollWidth = @computeScrollWidth()
+    @state.content.scrollHeight = @computeScrollHeight()
     @state.content.indentGuidesVisible = atom.config.get('editor.showIndentGuide', scope: @model.getRootScopeDescriptor())
 
   updateLinesState: ->
@@ -98,6 +98,9 @@ class TextEditorPresenter
     contentWidth += 1 unless @model.isSoftWrapped() # account for cursor width
     Math.max(contentWidth, @getClientWidth())
 
+  computeScrollHeight: ->
+    @getLineHeight() * @model.getScreenLineCount()
+
   lineDecorationClassesForRow: (row) ->
     return null if @model.isMini()
 
@@ -136,6 +139,7 @@ class TextEditorPresenter
   getClientWidth: -> @clientWidth
 
   setLineHeight: (@lineHeight) ->
+    @updateContentState()
     @updateLinesState()
 
   getLineHeight: -> @lineHeight