Bug 536207: Fix the height calculation by using the bottom index.Y20180815-2200I20180816-2000I20180815-2000I20180815-1250I20180814-2000

To fix the height of the displayed viewport instead of trying to
calculate the height the same approach as for the top index is used.
This way the height is ok for all cases including enabled word wrap.

Also fixed the update behavior when the text changes and introduced a
minimal height of the viewport rectangle, such that it does not shrink
if content is shown completely in the text viewer.

Change-Id: Ife949b9db6a7cbb46be749d082b40bc843279a79
Signed-off-by: Arne Deutsch <Arne.Deutsch@itemis.de>

1 files changed, 42 insertions, 22 deletions

diff --git a/org.eclipse.ui.workbench.texteditor/src/org/eclipse/ui/internal/views/minimap/MinimapWidget.java b/org.eclipse.ui.workbench.texteditor/src/org/eclipse/ui/internal/views/minimap/MinimapWidget.java
index 8df7e1955ff..0aaea1b31bb 100644
--- a/org.eclipse.ui.workbench.texteditor/src/org/eclipse/ui/internal/views/minimap/MinimapWidget.java
+++ b/org.eclipse.ui.workbench.texteditor/src/org/eclipse/ui/internal/views/minimap/MinimapWidget.java
@@ -7,6 +7,7 @@
  *
  * Contributors:
  * Angelo Zerr <angelo.zerr@gmail.com> - [minimap] Initialize minimap view - Bug 535450
+ * Arne Deutsch <arne.deutsch@itemis.de> - Correct view height - Bug 536207
  *******************************************************************************/
 package org.eclipse.ui.internal.views.minimap;
 
@@ -71,10 +72,6 @@ public class MinimapWidget {
 
 		private Map<Font, Font> fScaledFonts;
 
-		private static final int RESETED = -1;
-
-		private int scaledClientAreaHeight = RESETED;
-
 		@Override
 		public void textSet(TextChangedEvent event) {
 			synchText();
@@ -87,7 +84,7 @@ public class MinimapWidget {
 
 		@Override
 		public void textChanged(TextChangedEvent event) {
-			// Do nothing
+			updateMinimapAfterTextChange();
 		}
 
 		@Override
@@ -203,31 +200,33 @@ public class MinimapWidget {
 
 		@Override
 		public void controlResized(ControlEvent e) {
-			scaledClientAreaHeight = RESETED;
-			updateMinimap();
+			updateMinimapAfterResize();
 		}
 
 		@Override
 		public void viewportChanged(int verticalOffset) {
 			fMinimapTextWidget.getDisplay().asyncExec(() -> {
 				if (!fMinimapTextWidget.isDisposed()) {
-					updateMinimap();
+					updateMinimapAfterResize();
 				}
 			});
 		}
 
-		void updateMinimap() {
+		void updateMinimapAfterResize() {
+			updateMinimap(false);
+		}
+
+		void updateMinimapAfterTextChange() {
+			updateMinimap(true);
+		}
+
+		void updateMinimap(boolean textChanged) {
 			StyledText editorTextWidget = fEditorViewer.getTextWidget();
 			int editorTopIndex = JFaceTextUtil.getPartialTopIndex(editorTextWidget);
 			int editorBottomIndex = JFaceTextUtil.getPartialBottomIndex(editorTextWidget);
-			fMinimapTracker.updateMinimap(editorTopIndex, editorBottomIndex);
-		}
-
-		int getScaledClientAreaHeight() {
-			if (scaledClientAreaHeight == RESETED) {
-				scaledClientAreaHeight = Math.round(fEditorViewer.getTextWidget().getClientArea().height * getScale());
-			}
-			return scaledClientAreaHeight;
+			int maximalLines = fEditorViewer.getTextWidget().getClientArea().height
+					/ fEditorViewer.getTextWidget().getLineHeight();
+			fMinimapTracker.updateMinimap(editorTopIndex, editorBottomIndex, maximalLines, textChanged);
 		}
 
 		void install() {
@@ -300,8 +299,16 @@ public class MinimapWidget {
 
 		private int fEditorTopIndex;
 
+		private int fEditorBottomIndex;
+
 		private int fTopIndexY;
 
+		private int fBottomIndexY;
+
+		private int fMinimalHeight;
+
+		private int fMaximalLines;
+
 		private boolean fTextChanging;
 
 		@Override
@@ -327,9 +334,12 @@ public class MinimapWidget {
 			fEditorViewer.setTopIndex(newTopIndex);
 		}
 
-		public void updateMinimap(int editorTopIndex, int editorBottomIndex) {
-			if (editorTopIndex != fEditorTopIndex) {
+		void updateMinimap(int editorTopIndex, int editorBottomIndex, int maximalLines, boolean textChanged) {
+			if (editorTopIndex != fEditorTopIndex || editorBottomIndex != fEditorBottomIndex
+					|| maximalLines != fMaximalLines || textChanged) {
 				fEditorTopIndex = editorTopIndex;
+				fEditorBottomIndex = editorBottomIndex;
+				fMaximalLines = maximalLines;
 				// Update the position of minimap styled text
 				fMinimapTextWidget.setRedraw(false);
 				int newMinimapTopIndex = editorTopIndex;
@@ -345,11 +355,21 @@ public class MinimapWidget {
 				}
 				fMinimapTextWidget.setTopIndex(newMinimapTopIndex);
 				fTopIndexY = fMinimapTextWidget.getLinePixel(fEditorTopIndex);
+				// "fEditorBottomIndex + 1" because fEditorBottomIndex is START
+				// of last line ... we want to include it
+				fBottomIndexY = fMinimapTextWidget.getLinePixel(fEditorBottomIndex + 1);
+				// to avoid that the highlight viewport shrinks to the text
+				// height in case all content is visible in the editor,
+				// calculate a minimal height based on the number of lines
+				// maximal shown and the line height in the minimap
+				fMinimalHeight = maximalLines > fMinimapTextWidget.getLineCount()
+						? maximalLines * fMinimapTextWidget.getLineHeight()
+						: 0;
 				fMinimapTextWidget.setRedraw(true);
 			}
 		}
 
-		public void replaceTextRange(TextChangingEvent event) {
+		void replaceTextRange(TextChangingEvent event) {
 			fTextChanging = true;
 			int start = event.start;
 			int length = event.replaceCharCount;
@@ -381,10 +401,10 @@ public class MinimapWidget {
 		@Override
 		public void paintControl(PaintEvent event) {
 			GC gc = event.gc;
-			int clientAreaHeight = fEditorTracker.getScaledClientAreaHeight();
 			int clientAreaWidth = fMinimapTextWidget.getClientArea().width;
 			gc.setBackground(fMinimapTextWidget.getSelectionBackground());
-			Rectangle rect = new Rectangle(0, fTopIndexY, clientAreaWidth, clientAreaHeight);
+			Rectangle rect = new Rectangle(0, fTopIndexY, clientAreaWidth,
+					Math.max(fBottomIndexY - fTopIndexY, fMinimalHeight));
 			gc.drawRectangle(rect.x, rect.y, Math.max(1, rect.width - 1), Math.max(1, rect.height - 1));
 			gc.setAdvanced(true);
 			if (gc.getAdvanced()) {