From 1a861b64035f1542972b0ce5124cedb13777a05d Mon Sep 17 00:00:00 2001
From: Sergey Solovyev <se.solovyev@gmail.com>
Date: Sun, 20 Jan 2013 22:01:31 +0400
Subject: [PATCH] Graph height addeed

---
 android-app-core/res/values/text_strings.xml  |   2 +
 .../res/layout/cpp_plot_range_fragment.xml    |  45 +++++++
 .../plot/CalculatorGraph2dView.java           | 121 +++++++++++-------
 .../plot/CalculatorGraph3dView.java           |   6 +-
 .../plot/CalculatorPlotFragment.java          |   6 +-
 .../plot/CalculatorPlotRangeActivity.java     |  12 +-
 .../calculator/plot/Graph2dDimensions.java    |  88 +++++++------
 .../calculator/plot/GraphCalculatorImpl.java  |   9 +-
 .../android/calculator/plot/GraphView.java    |   1 +
 .../android/calculator/plot/ZoomTracker.java  |  17 ++-
 10 files changed, 209 insertions(+), 98 deletions(-)

diff --git a/android-app-core/res/values/text_strings.xml b/android-app-core/res/values/text_strings.xml
index c480b9f9..34fdd9e3 100644
--- a/android-app-core/res/values/text_strings.xml
+++ b/android-app-core/res/values/text_strings.xml
@@ -317,6 +317,8 @@
     <string name="cpp_plot_range">Graph range</string>
     <string name="cpp_plot_range_x_min">X Min</string>
     <string name="cpp_plot_range_x_max">X Max</string>
+    <string name="cpp_plot_range_y_min">Y Min</string>
+    <string name="cpp_plot_range_y_max">Y Max</string>
     <string name="cpp_invalid_number">Invalid number!</string>
     <string name="cpp_plot_boundaries_should_differ">Graph boundaries should not be the same!</string>
     <string name="cpp_apply">Apply</string>
diff --git a/android-app/res/layout/cpp_plot_range_fragment.xml b/android-app/res/layout/cpp_plot_range_fragment.xml
index 5c12081c..15d0f0bb 100644
--- a/android-app/res/layout/cpp_plot_range_fragment.xml
+++ b/android-app/res/layout/cpp_plot_range_fragment.xml
@@ -53,6 +53,51 @@
         </LinearLayout>
 
 
+    </LinearLayout>
+
+    <LinearLayout
+        a:layout_width="match_parent"
+        a:layout_height="wrap_content"
+        a:orientation="horizontal"
+        a:baselineAligned="false">
+
+        <LinearLayout
+            a:layout_width="0dp"
+            a:layout_height="wrap_content"
+            a:layout_weight="1"
+            a:orientation="vertical">
+
+            <TextView
+                a:text="@string/cpp_plot_range_y_min"
+                a:layout_width="match_parent"
+                a:layout_height="wrap_content" />
+
+            <EditText
+                a:id="@+id/cpp_plot_range_y_min_editext"
+                a:inputType="numberDecimal|numberSigned"
+                a:layout_width="match_parent"
+                a:layout_height="wrap_content" />
+        </LinearLayout>
+
+        <LinearLayout
+            a:layout_width="0dp"
+            a:layout_height="wrap_content"
+            a:layout_weight="1"
+            a:orientation="vertical">
+
+            <TextView
+                a:text="@string/cpp_plot_range_y_max"
+                a:layout_width="match_parent"
+                a:layout_height="wrap_content" />
+
+            <EditText
+                a:id="@+id/cpp_plot_range_y_max_editext"
+                a:inputType="numberDecimal|numberSigned"
+                a:layout_width="match_parent"
+                a:layout_height="wrap_content" />
+        </LinearLayout>
+
+
     </LinearLayout>
 
     <Button
diff --git a/android-app/src/main/java/org/solovyev/android/calculator/plot/CalculatorGraph2dView.java b/android-app/src/main/java/org/solovyev/android/calculator/plot/CalculatorGraph2dView.java
index 5da8c84e..f9f8fbe3 100644
--- a/android-app/src/main/java/org/solovyev/android/calculator/plot/CalculatorGraph2dView.java
+++ b/android-app/src/main/java/org/solovyev/android/calculator/plot/CalculatorGraph2dView.java
@@ -9,6 +9,7 @@ import android.view.View;
 import android.widget.Scroller;
 import android.widget.ZoomButtonsController;
 import org.jetbrains.annotations.NotNull;
+import org.solovyev.common.definitions.Pair;
 import org.solovyev.common.math.Point2d;
 
 import java.text.DecimalFormat;
@@ -186,8 +187,9 @@ public class CalculatorGraph2dView extends View implements GraphView {
         if (!graphViewHelper.getPlotFunctions().isEmpty()) {
 
             if (scroller.computeScrollOffset()) {
-                final float ratio = dimensions.getGraphToViewRatio();
-                dimensions.setXY(scroller.getCurrX() * ratio, scroller.getCurrY() * ratio);
+                final float xScale = dimensions.getXGraphToViewScale();
+                final float yScale = dimensions.getYGraphToViewScale();
+                dimensions.setXY(scroller.getCurrX() * xScale, scroller.getCurrY() * yScale);
                 if (!scroller.isFinished()) {
                     invalidate();
                 }
@@ -228,19 +230,20 @@ public class CalculatorGraph2dView extends View implements GraphView {
     private void drawGraph(@NotNull Canvas canvas) {
         mDrawn = true;
 
-        final float graphHeight = dimensions.getGraphHeight();
+        final float graphWidth = dimensions.getGWidth();
+        final float graphHeight = dimensions.getGHeight();
 
         final float xMin = dimensions.getXMin();
         final float xMax = dimensions.getXMax(xMin);
 
-        final float yMin = dimensions.getYMin(graphHeight);
-        final float yMax = dimensions.getYMax(graphHeight, yMin);
+        final float yMin = dimensions.getYMin();
+        final float yMax = dimensions.getYMax(yMin);
         final float widthPxs = dimensions.getVWidthPxs();
         final float heightPxs = dimensions.getVHeightPxs();
 
         graphsData.checkBoundaries(graphHeight, yMin, yMax);
 
-        final int tickDigits = drawGridAndAxis(canvas);
+        final Pair<Integer, Integer> tickDigits = drawGridAndAxis(canvas);
 
 		{
 			// TOUCH POSITION
@@ -253,16 +256,17 @@ public class CalculatorGraph2dView extends View implements GraphView {
 				canvas.drawLine(0, lastTouchYPxs, widthPxs, lastTouchYPxs, paint);
 
 				final Point2d lastTouch = dimensions.toGraphCoordinates(lastTouchXPxs, lastTouchYPxs);
-				final String touchLabel = "[" + formatTick(lastTouch.getX(), tickDigits + 1) + ", " + formatTick(lastTouch.getY(), tickDigits + 1) + "]";
+				final String touchLabel = "[" + formatTick(lastTouch.getX(), tickDigits.getFirst() + 1) + ", " + formatTick(lastTouch.getY(), tickDigits.getSecond() + 1) + "]";
 				canvas.drawText(touchLabel, 0, touchLabel.length(), lastTouchXPxs - 40, lastTouchYPxs - 40, textPaint);
 			}
 		}
 
-        final float ratio = dimensions.getGraphToViewRatio();
+        final float xScale = dimensions.getXGraphToViewScale();
+        final float yScale = dimensions.getYGraphToViewScale();
 
         matrix.reset();
         matrix.preTranslate(-dimensions.getX0(), -dimensions.getY0());
-        matrix.postScale(1/ratio, -1/ratio);
+        matrix.postScale(1/xScale, -1/yScale);
         matrix.postTranslate(widthPxs / 2, heightPxs / 2);
 
         paint.setAntiAlias(false);
@@ -296,13 +300,14 @@ public class CalculatorGraph2dView extends View implements GraphView {
         graphsData.setLastXMax(xMax);
     }
 
-    private int drawGridAndAxis(@NotNull Canvas canvas) {
-        final float graphHeight = dimensions.getGraphHeight();
+    @NotNull
+    private Pair<Integer, Integer> drawGridAndAxis(@NotNull Canvas canvas) {
+        final Pair<Integer, Integer> result = new Pair<Integer, Integer>(1, 1);
 
         final float xMin = dimensions.getXMin();
 
-        final float yMin = dimensions.getYMin(graphHeight);
-        final float yMax = dimensions.getYMax(graphHeight, yMin);
+        final float yMin = dimensions.getYMin();
+        final float yMax = dimensions.getYMax(yMin);
         final float widthPxs = dimensions.getVWidthPxs();
         final float heightPxs = dimensions.getVHeightPxs();
 
@@ -314,26 +319,23 @@ public class CalculatorGraph2dView extends View implements GraphView {
         paint.setAntiAlias(false);
         paint.setStyle(Paint.Style.STROKE);
 
-        final float ratio = dimensions.getGraphToViewRatio();
+        final float xScale = dimensions.getXGraphToViewScale();
+        final float yScale = dimensions.getYGraphToViewScale();
 
-        float x0px = -xMin / ratio;
+        float x0px = -xMin / xScale;
         if (x0px < 25) {
             x0px = 25;
         } else if (x0px > widthPxs - 3) {
             x0px = widthPxs - 3;
         }
 
-        float y0px = yMax / ratio;
+        float y0px = yMax / yScale;
         if (y0px < 3) {
             y0px = 3;
         } else if (y0px > heightPxs - 15) {
             y0px = heightPxs - 15;
         }
 
-
-        final float tickStep = getTickStep(dimensions.getGWidth());
-        final int tickDigits = countTickDigits(tickStep);
-
         {
             // GRID
 
@@ -344,33 +346,48 @@ public class CalculatorGraph2dView extends View implements GraphView {
             textPaint.setTextSize(12);
             textPaint.setTextAlign(Paint.Align.CENTER);
 
-            // round xMin and init first tick
-            float tick = ((int) (xMin / tickStep)) * tickStep;
 
-            final float y2 = y0px + TICK_SIZE_PXS;
+            {
+                final float tickStep = getTickStep(dimensions.getGWidth());
+                final int tickDigits = countTickDigits(tickStep);
+                result.setFirst(tickDigits);
+                // round xMin and init first tick
+                float tick = ((int) (xMin / tickStep)) * tickStep;
 
-            final float stepPxs = tickStep / ratio;
+                final float y2 = y0px + TICK_SIZE_PXS;
 
-            for (float xPxs = (tick - xMin) / ratio; xPxs <= widthPxs; xPxs += stepPxs, tick += tickStep) {
-                // draw grid line
-                canvas.drawLine(xPxs, 0, xPxs, heightPxs, paint);
+                float stepPxs = tickStep / xScale;
 
-                final CharSequence tickLabel = formatTick(tick, tickDigits);
+                for (float xPxs = (tick - xMin) / xScale; xPxs <= widthPxs; xPxs += stepPxs, tick += tickStep) {
+                    // draw grid line
+                    canvas.drawLine(xPxs, 0, xPxs, heightPxs, paint);
 
-                // draw tick label
-                canvas.drawText(tickLabel, 0, tickLabel.length(), xPxs, y2 + 10, textPaint);
+                    final CharSequence tickLabel = formatTick(tick, tickDigits);
+
+                    // draw tick label
+                    canvas.drawText(tickLabel, 0, tickLabel.length(), xPxs, y2 + 10, textPaint);
+                }
             }
 
-            final float x1 = x0px - TICK_SIZE_PXS;
-            tick = ((int) (yMin / tickStep)) * tickStep;
-            textPaint.setTextAlign(Paint.Align.RIGHT);
-            for (float y = heightPxs - (tick - yMin) / ratio; y >= 0; y -= stepPxs, tick += tickStep) {
-                canvas.drawLine(0, y, widthPxs, y, paint);
+            {
+                final float tickStep = getTickStep(dimensions.getGHeight());
+                final int tickDigits = countTickDigits(tickStep);
+                result.setSecond(tickDigits);
+                // round yMin and init first tick
+                float tick = ((int) (yMin / tickStep)) * tickStep;
 
-                final CharSequence tickLabel = formatTick(tick, tickDigits);
+                final float x1 = x0px - TICK_SIZE_PXS;
 
-                // draw tick label
-                canvas.drawText(tickLabel, 0, tickLabel.length(), x1, y + 4, textPaint);
+                final float stepPxs = tickStep / yScale;
+                textPaint.setTextAlign(Paint.Align.RIGHT);
+                for (float y = heightPxs - (tick - yMin) / yScale; y >= 0; y -= stepPxs, tick += tickStep) {
+                    canvas.drawLine(0, y, widthPxs, y, paint);
+
+                    final CharSequence tickLabel = formatTick(tick, tickDigits);
+
+                    // draw tick label
+                    canvas.drawText(tickLabel, 0, tickLabel.length(), x1, y + 4, textPaint);
+                }
             }
 
             paint.setPathEffect(null);
@@ -383,7 +400,8 @@ public class CalculatorGraph2dView extends View implements GraphView {
             canvas.drawLine(x0px, 0, x0px, heightPxs, paint);
             canvas.drawLine(0, y0px, widthPxs, y0px, paint);
         }
-        return tickDigits;
+
+        return result;
     }
 
     /*
@@ -480,6 +498,11 @@ public class CalculatorGraph2dView extends View implements GraphView {
         this.dimensions.setXRange(xMin, xMax);
     }
 
+    @Override
+    public void setYRange(float yMin, float yMax) {
+        this.dimensions.setYRange(yMin, yMax);
+    }
+
     /*
     **********************************************************************
     *
@@ -502,11 +525,11 @@ public class CalculatorGraph2dView extends View implements GraphView {
     public void onZoom(boolean zoomIn) {
         if (zoomIn) {
             if (canZoomIn()) {
-                dimensions.setGWidth(dimensions.getGWidth() / 2);
+                dimensions.setGraphDimensions(dimensions.getGWidth() / 2, dimensions.getGHeight() / 2);
             }
         } else {
             if (canZoomOut()) {
-                dimensions.setGWidth(dimensions.getGWidth() * 2);
+                dimensions.setGraphDimensions(dimensions.getGWidth() * 2, dimensions.getGHeight() * 2);
             }
         }
         zoomController.setZoomInEnabled(canZoomIn());
@@ -553,7 +576,8 @@ public class CalculatorGraph2dView extends View implements GraphView {
     }
 
     public void onTouchUp(float x, float y) {
-        final float ratio = dimensions.getGraphToViewRatio();
+        final float xScale = dimensions.getXGraphToViewScale();
+        final float yScale = dimensions.getYGraphToViewScale();
 
 		lastTouchXPxs = NO_TOUCH;
 		lastTouchYPxs = NO_TOUCH;
@@ -568,22 +592,23 @@ public class CalculatorGraph2dView extends View implements GraphView {
         } else if (asy < asx / 3) {
             sy = 0;
         }
-        scroller.fling(Math.round(dimensions.getX0() / ratio), Math.round(dimensions.getY0() / ratio), Math.round(sx), Math.round(sy), Integer.MIN_VALUE, Integer.MAX_VALUE, Integer.MIN_VALUE, Integer.MAX_VALUE);
+        scroller.fling(Math.round(dimensions.getX0() / xScale), Math.round(dimensions.getY0() / yScale), Math.round(sx), Math.round(sy), Integer.MIN_VALUE, Integer.MAX_VALUE, Integer.MIN_VALUE, Integer.MAX_VALUE);
         invalidate();
     }
 
     public void onTouchZoomDown(float x1, float y1, float x2, float y2) {
-        zoomTracker.start(dimensions.getGWidth(), x1, y1, x2, y2);
+        zoomTracker.start(dimensions.getGWidth(), dimensions.getGHeight(), x1, y1, x2, y2);
     }
 
     public void onTouchZoomMove(float x1, float y1, float x2, float y2) {
         if (!zoomTracker.update(x1, y1, x2, y2)) {
             return;
         }
-        float targetGWidth = zoomTracker.value;
-        if (targetGWidth > .25f && targetGWidth < 200) {
-            dimensions.setGWidth(targetGWidth);
-        }
+
+        final float targetGWidth = zoomTracker.xValue;
+        final float targetGHeight = zoomTracker.yValue;
+
+        dimensions.setGraphDimensions(targetGWidth, targetGHeight);
     }
 
     private void scroll(float deltaX, float deltaY) {
diff --git a/android-app/src/main/java/org/solovyev/android/calculator/plot/CalculatorGraph3dView.java b/android-app/src/main/java/org/solovyev/android/calculator/plot/CalculatorGraph3dView.java
index fd056841..67f00582 100755
--- a/android-app/src/main/java/org/solovyev/android/calculator/plot/CalculatorGraph3dView.java
+++ b/android-app/src/main/java/org/solovyev/android/calculator/plot/CalculatorGraph3dView.java
@@ -173,6 +173,10 @@ public class CalculatorGraph3dView extends GLView implements GraphView {
         dirty = true;
     }
 
+    @Override
+    public void setYRange(float yMin, float yMax) {
+    }
+
     @Override
     public float getXMin() {
         return dimensions.getXMin();
@@ -229,7 +233,7 @@ public class CalculatorGraph3dView extends GLView implements GraphView {
             ensureGraphsSize(gl);
 
             final Graph2dDimensions dimensionsCopy = dimensions.copy();
-            dimensionsCopy.setGWidth(dimensions.getGWidth() * zoomLevel / 4);
+            dimensionsCopy.setGraphDimensions(dimensions.getGWidth() * zoomLevel / 4, dimensions.getGHeight() * zoomLevel / 4);
 
             for (int i = 0; i < graphViewHelper.getPlotFunctions().size(); i++) {
                 graphs.get(i).update(gl, graphViewHelper.getPlotFunctions().get(i), dimensionsCopy);
diff --git a/android-app/src/main/java/org/solovyev/android/calculator/plot/CalculatorPlotFragment.java b/android-app/src/main/java/org/solovyev/android/calculator/plot/CalculatorPlotFragment.java
index 2bcd05cf..b292cc7c 100644
--- a/android-app/src/main/java/org/solovyev/android/calculator/plot/CalculatorPlotFragment.java
+++ b/android-app/src/main/java/org/solovyev/android/calculator/plot/CalculatorPlotFragment.java
@@ -46,7 +46,11 @@ public class CalculatorPlotFragment extends AbstractCalculatorPlotFragment {
         }
 
         graphView.init(PlotViewDef.newInstance(Color.WHITE, Color.WHITE, Color.DKGRAY, getBgColor()));
-        graphView.setXRange(plotData.getBoundaries().getXMin(), plotData.getBoundaries().getXMax());
+
+        final PlotBoundaries boundaries = plotData.getBoundaries();
+        graphView.setXRange(boundaries.getXMin(), boundaries.getXMax());
+        graphView.setYRange(boundaries.getYMin(), boundaries.getYMax());
+
         graphView.setPlotFunctions(plotData.getFunctions());
 
         if (graphView instanceof View) {
diff --git a/android-app/src/main/java/org/solovyev/android/calculator/plot/CalculatorPlotRangeActivity.java b/android-app/src/main/java/org/solovyev/android/calculator/plot/CalculatorPlotRangeActivity.java
index 91c852a2..223aa746 100644
--- a/android-app/src/main/java/org/solovyev/android/calculator/plot/CalculatorPlotRangeActivity.java
+++ b/android-app/src/main/java/org/solovyev/android/calculator/plot/CalculatorPlotRangeActivity.java
@@ -43,12 +43,16 @@ public class CalculatorPlotRangeActivity extends SherlockFragmentActivity {
 
             final EditText xMinEditText = (EditText) root.findViewById(R.id.cpp_plot_range_x_min_editext);
             final EditText xMaxEditText = (EditText) root.findViewById(R.id.cpp_plot_range_x_max_editext);
+            final EditText yMinEditText = (EditText) root.findViewById(R.id.cpp_plot_range_y_min_editext);
+            final EditText yMaxEditText = (EditText) root.findViewById(R.id.cpp_plot_range_y_max_editext);
 
             final PlotData plotData = plotter.getPlotData();
             final PlotBoundaries boundaries = plotData.getBoundaries();
 
             xMinEditText.setText(String.valueOf(boundaries.getXMin()));
             xMaxEditText.setText(String.valueOf(boundaries.getXMax()));
+            yMinEditText.setText(String.valueOf(boundaries.getYMin()));
+            yMaxEditText.setText(String.valueOf(boundaries.getYMax()));
 
             root.findViewById(R.id.cpp_apply_button).setOnClickListener(new View.OnClickListener() {
                 @Override
@@ -57,12 +61,18 @@ public class CalculatorPlotRangeActivity extends SherlockFragmentActivity {
                     try {
                         final Float xMin = Float.valueOf(xMinEditText.getText().toString());
                         final Float xMax = Float.valueOf(xMaxEditText.getText().toString());
+                        final Float yMin = Float.valueOf(yMinEditText.getText().toString());
+                        final Float yMax = Float.valueOf(yMaxEditText.getText().toString());
 
                         if ( xMin.equals(xMax) ) {
                             throw new IllegalArgumentException();
                         }
 
-                        plotter.setPlotBoundaries(PlotBoundaries.newInstance(xMin, xMax));
+                        if ( yMin.equals(yMax) ) {
+                            throw new IllegalArgumentException();
+                        }
+
+                        plotter.setPlotBoundaries(PlotBoundaries.newInstance(xMin, xMax, yMin, yMax));
 
                         CalculatorPlotRangeFragment.this.getActivity().finish();
 
diff --git a/android-app/src/main/java/org/solovyev/android/calculator/plot/Graph2dDimensions.java b/android-app/src/main/java/org/solovyev/android/calculator/plot/Graph2dDimensions.java
index 15c342bd..c40d2a20 100644
--- a/android-app/src/main/java/org/solovyev/android/calculator/plot/Graph2dDimensions.java
+++ b/android-app/src/main/java/org/solovyev/android/calculator/plot/Graph2dDimensions.java
@@ -14,24 +14,25 @@ public class Graph2dDimensions {
     //                    |<--------------gWidth-------------->|
     //                   xMin                                xMax
     // -------------------|------------------------------------|--------------------
-    //                    |<-------------vWidthPs------------->|
+    //                    |<-------------vWidthPxs------------>|
     //
     /*
     *
     *
-    *                     0------------------------------------|--> xPxs
-    *                     |
-    *                     |
-    *                     |                  y
-    *                     |                  ^
-    *                     |                  |
-    *                     |                  |
-    *                     |                  |
-    *                     |------------------0-----------------|--> x
-    *                     |                  |
-    *                     |                  |
-    *                     |                  |
-    *                     |                  |
+    *        yMax   ------0------------------------------------|--> xPxs
+    *               ^     |
+    *               |     |
+    *               v     |                  y
+    *               H     |                  ^
+    *               e     |                  |
+    *               i     |                  |
+    *               g     |                  |
+    *               h     |------------------0-----------------|--> x
+    *               t     |                  |
+    *               |     |                  |
+    *               |     |                  |
+    *               v     |                  |
+    *        yMin   -------                  -
     *                     |                  |
     *                     v
     *                    yPxs
@@ -50,8 +51,9 @@ public class Graph2dDimensions {
     private float x0;
     private float y0;
 
-    // graph width in function units (NOT screen pixels)
+    // graph width and height in function units (NOT screen pixels)
     private float gWidth = 20;
+    private float gHeight = 20;
 
     public Graph2dDimensions(@NotNull GraphView graphView) {
         this.graphView = graphView;
@@ -67,11 +69,15 @@ public class Graph2dDimensions {
 
     @NotNull
     Point2d toGraphCoordinates(float xPxs, float yPxs) {
-        return new Point2d( scalePxs(xPxs) + getXMin(), (getGraphHeight() - scalePxs(yPxs)) + getYMin() );
+        return new Point2d( scaleXPxs(xPxs) + getXMin(), (getGHeight() - scaleYPxs(yPxs)) + getYMin() );
     }
 
-    private float scalePxs(float pxs) {
-        return pxs * getGraphToViewRatio();
+    private float scaleXPxs(float pxs) {
+        return pxs * getXGraphToViewScale();
+    }
+
+    private float scaleYPxs(float pxs) {
+        return pxs * getYGraphToViewScale();
     }
 
     // X
@@ -91,28 +97,18 @@ public class Graph2dDimensions {
     // Y
 
     public float getYMin() {
-        return getYMin(getGraphHeight());
-    }
-
-
-    public float getYMin(float graphHeight) {
-        return y0 - graphHeight / 2;
+        return y0 - gHeight / 2;
     }
 
     public float getYMax() {
-        final float graphHeight = getGraphHeight();
-        return getYMax(graphHeight, getYMin(graphHeight));
+        return getYMax(getYMin());
     }
 
-    public float getYMax(float graphHeight, float yMin) {
-        return yMin + graphHeight;
+    public float getYMax(float yMin) {
+        return yMin + gHeight;
     }
 
-    float getGraphHeight() {
-        return gWidth * getAspectRatio();
-    }
-
-    float getGraphToViewRatio() {
+    float getXGraphToViewScale() {
         if (vWidthPxs != 0) {
             return gWidth / ((float)vWidthPxs);
         } else {
@@ -120,7 +116,15 @@ public class Graph2dDimensions {
         }
     }
 
-    private float getAspectRatio() {
+    float getYGraphToViewScale() {
+        if (vHeightPxs != 0) {
+            return gHeight / ((float)vHeightPxs);
+        } else {
+            return 0f;
+        }
+    }
+
+    private float getViewAspectRatio() {
         if (vWidthPxs != 0) {
             return ((float) vHeightPxs) / vWidthPxs;
         } else {
@@ -148,6 +152,10 @@ public class Graph2dDimensions {
         return gWidth;
     }
 
+    float getGHeight() {
+        return gHeight;
+    }
+
     /*
     **********************************************************************
     *
@@ -159,7 +167,13 @@ public class Graph2dDimensions {
     public void setXRange(float xMin, float xMax) {
         this.gWidth = xMax - xMin;
         this.x0 = xMin + gWidth / 2;
-        this.y0 = 0;
+
+        this.graphView.invalidateGraphs();
+    }
+
+    public void setYRange(float yMin, float yMax) {
+        this.gHeight = yMax - yMin;
+        this.y0 = yMin + gHeight / 2;
 
         this.graphView.invalidateGraphs();
     }
@@ -172,8 +186,9 @@ public class Graph2dDimensions {
     }
 
 
-    public void setGWidth(float gWidth) {
+    public void setGraphDimensions(float gWidth, float gHeight) {
         this.gWidth = gWidth;
+        this.gHeight = gHeight;
 
         this.graphView.invalidateGraphs();
     }
@@ -204,6 +219,7 @@ public class Graph2dDimensions {
         copy.x0 = this.x0;
         copy.y0 = this.y0;
         copy.gWidth = this.gWidth;
+        copy.gHeight = this.gHeight;
 
         return copy;
     }
diff --git a/android-app/src/main/java/org/solovyev/android/calculator/plot/GraphCalculatorImpl.java b/android-app/src/main/java/org/solovyev/android/calculator/plot/GraphCalculatorImpl.java
index b7cd1e3c..7d3426a4 100644
--- a/android-app/src/main/java/org/solovyev/android/calculator/plot/GraphCalculatorImpl.java
+++ b/android-app/src/main/java/org/solovyev/android/calculator/plot/GraphCalculatorImpl.java
@@ -19,11 +19,12 @@ public class GraphCalculatorImpl extends AbstractGraphCalculator {
                              @NotNull Graph2dDimensions dimensions) {
         graph.push(xMin, (float)f.eval(xMin));
 
-        final float ratio = dimensions.getGraphToViewRatio();
-        final float maxStep = 15.8976f * ratio;
-        final float minStep = .05f * ratio;
+        final float xScale = dimensions.getXGraphToViewScale();
+        final float yScale = dimensions.getYGraphToViewScale();
+        final float maxStep = 15.8976f * xScale;
+        final float minStep = .05f * xScale;
 
-        float yTheta = ratio;
+        float yTheta = yScale;
         yTheta = yTheta * yTheta;
 
 
diff --git a/android-app/src/main/java/org/solovyev/android/calculator/plot/GraphView.java b/android-app/src/main/java/org/solovyev/android/calculator/plot/GraphView.java
index e1d04c9c..de60da3d 100755
--- a/android-app/src/main/java/org/solovyev/android/calculator/plot/GraphView.java
+++ b/android-app/src/main/java/org/solovyev/android/calculator/plot/GraphView.java
@@ -23,6 +23,7 @@ public interface GraphView extends ZoomButtonsController.OnZoomListener, TouchHa
     public Bitmap captureScreenshot();
 
 	void setXRange(float xMin, float xMax);
+	void setYRange(float yMin, float yMax);
 
     float getXMin();
 
diff --git a/android-app/src/main/java/org/solovyev/android/calculator/plot/ZoomTracker.java b/android-app/src/main/java/org/solovyev/android/calculator/plot/ZoomTracker.java
index 73e96238..5076ab85 100755
--- a/android-app/src/main/java/org/solovyev/android/calculator/plot/ZoomTracker.java
+++ b/android-app/src/main/java/org/solovyev/android/calculator/plot/ZoomTracker.java
@@ -1,22 +1,24 @@
-// Copyright (C) 2010 Mihai Preda
-
 package org.solovyev.android.calculator.plot;
 
 class ZoomTracker {
     private float sx1, sy1, sx2, sy2;
     private float initialDist;
-    private float initialValue;
 
-    float value;
+    private float initialXValue;
+    private float initialYValue;
+
+    float xValue;
+    float yValue;
     float moveX, moveY;
 
-    void start(float value, float x1, float y1, float x2, float y2) {
+    void start(float xValue, float yValue, float x1, float y1, float x2, float y2) {
         sx1 = x1;
         sy1 = y1;
         sx2 = x2;
         sy2 = y2;
         initialDist = distance(x1, y1, x2, y2);
-        initialValue = value;
+        initialXValue = xValue;
+        initialYValue = yValue;
     }
 
     boolean update(float x1, float y1, float x2, float y2) {
@@ -28,7 +30,8 @@ class ZoomTracker {
         moveX = common(x1, sx1, x2, sx2);
         moveY = common(y1, sy1, y2, sy2);
         float dist = distance(x1, y1, x2, y2);
-        value = initialDist / dist * initialValue;
+        xValue = initialDist / dist * initialXValue;
+        yValue = initialDist / dist * initialYValue;
         sx1 = x1;
         sx2 = x2;
         sy1 = y1;