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Introduce a new StepMode (halfhp#32)
* Introduce a new StepMode Why: Increment by value -> no good when zooming Increment by pixel -> no good when zooming subdivide -> depending on data chooses ticks at wired locations e.g (1.3 , 2.3, 3,3 instead of 1, 2, 3) Workaround: When you know your data: supply an array of predefined increments (by value) for StepModel to choose from to best fit the desired number of lines. For example: Start zoomed out with ticks every 100 and as you zoom in switch to 50,10,1 * Introduce a new StepMode Why: Increment by value -> no good when zooming Increment by pixel -> no good when zooming subdivide -> depending on data chooses ticks at wired locations e.g (1.3 , 2.3, 3,3 instead of 1, 2, 3) Workaround: When you know your data: supply an array of predefined increments (by value) for StepModel to choose from to best fit the desired number of lines. For example: Start zoomed out with ticks every 100 and as you zoom in switch to 50,10,1 * comments * restore messed up build files * sanity check for StepModelFit.setSteps added unit test for StepModelFit
1 parent 8e5fcc1 commit bae8096

6 files changed

Lines changed: 160 additions & 4 deletions

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‎androidplot-core/src/main/java/com/androidplot/xy/StepMode.java‎

Lines changed: 3 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -20,9 +20,11 @@
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* INCREMENTAL_VALUE - (default) draw a tick every n values.
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* INCREMENTAL_PIXEL - draw a tick every n pixels.
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* SUBDIVIDE - draw n number of evenly spaced lines.
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* INCREMENT_BY_FIT choose increment from a list of possible values
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*/
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public enum StepMode {
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SUBDIVIDE, // default
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INCREMENT_BY_VAL,
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INCREMENT_BY_PIXELS
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INCREMENT_BY_PIXELS,
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INCREMENT_BY_FIT
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}

‎androidplot-core/src/main/java/com/androidplot/xy/StepModelFit.java‎

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package com.androidplot.xy;
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import com.androidplot.Region;
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import java.util.Arrays;
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/**
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* Subclass of StepModel that chooses from predefined step values. Depending on the currently
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* displayed range (by value) choose increment so that the number of lines
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* is closest to StepModel.value
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*/
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public class StepModelFit extends StepModel {
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private double[] steps; // list of steps to choose from
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private Region scale; // axis region on display
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public StepModelFit(Region axisRegion, double[] increments, double numLines) {
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super(StepMode.INCREMENT_BY_FIT, numLines);
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setSteps(increments);
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setScale(axisRegion);
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}
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public double[] getSteps() {
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return steps;
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}
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public void setSteps(double[] steps) {
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// sanity checks: no null, 0 or negative
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if (steps == null || steps.length == 0)
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return;
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for (double step : steps) {
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if (step <= 0.0d)
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return;
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}
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this.steps = steps;
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}
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public Region getScale() {
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return scale;
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}
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public void setScale(Region scale) {
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this.scale = scale;
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}
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// does not return StepModel.value instead calculates best fit
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@Override
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public double getValue() {
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// no possible increments where supplied
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// or no region defined
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if (steps == null || scale == null || !scale.isDefined())
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return super.getValue();
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double curStep = steps[0];
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double oldDistance = Math.abs((scale.length().doubleValue() / curStep)-super.getValue() );
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// determine which step size comes closest to the desired number of steps
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// since steps[] is a small array brute force search is ok
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for (double step : steps) {
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double newDistance = Math.abs((scale.length().doubleValue() / step)-super.getValue() );
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// closer than previous stepping?
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if (newDistance < oldDistance){
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curStep = step;
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oldDistance = newDistance;
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}
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}
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return curStep;
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}
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@Override
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public String toString() {
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return "StepModelFit{" +
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"steps=" + Arrays.toString(steps) +
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", scale=" + scale +
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", current stepping=" + getValue() +
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'}';
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}
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}

‎androidplot-core/src/main/java/com/androidplot/xy/XYGraphWidget.java‎

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Original file line numberDiff line numberDiff line change
@@ -546,7 +546,7 @@ protected void drawLineLabel(Canvas canvas, Edge edge, Number val, float x, floa
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}
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/**
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* Draws the drid and domain/range labels for the plot.
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* Draws the grid and domain/range labels for the plot.
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*
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* @param canvas
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*/

‎androidplot-core/src/main/java/com/androidplot/xy/XYStepCalculator.java‎

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Original file line numberDiff line numberDiff line change
@@ -59,6 +59,7 @@ public static Step getStep(StepMode typeXY, double stepValue, Region realBounds,
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double stepCount = 0;
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switch(typeXY) {
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case INCREMENT_BY_VAL:
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case INCREMENT_BY_FIT:
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stepVal = stepValue;
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stepPix = stepValue / realBounds.ratio(pixelBounds).doubleValue();
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stepCount = pixelBounds.length().doubleValue() / stepPix;

‎androidplot-core/src/test/java/com/androidplot/xy/StepModelFitTest.java‎

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package com.androidplot.xy;
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import com.androidplot.Region;
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import org.junit.After;
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import org.junit.Before;
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import org.junit.Test;
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import static org.junit.Assert.*;
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public class StepModelFitTest {
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Region regionSmall = new Region(0,11);
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Region regionBig = new Region(-111,420);
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Region regionZero = new Region(0, 0);
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Region regionUndef = new Region(0, null);
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double[] stpSmall = {1,2,5}, stpBig = {1,10,100}, nonsense = {0};
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@Before
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public void setUp() throws Exception {
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}
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@After
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public void tearDown() throws Exception {
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}
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@Test
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public void getValue() throws Exception {
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StepModelFit model = new StepModelFit(regionSmall,stpSmall,3);
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assertEquals(5.0, model.getValue(), 0.0);
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model.setValue(5.0);
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assertEquals(2.0, model.getValue(), 0.0);
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model.setValue(7.0);
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assertEquals(2.0, model.getValue(), 0.0);
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model.setSteps(stpBig);
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assertEquals(1.0, model.getValue(), 0.0);
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model.setScale(regionBig);
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assertEquals(100.0, model.getValue(), 0.0);
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model.setValue(1000.0);
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assertEquals(1.0, model.getValue(), 0.0);
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// bad parameters
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model.setSteps(nonsense);
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assertArrayEquals(stpBig,model.getSteps(), 0.0);
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model.setScale(regionZero);
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assertEquals(stpBig[0], model.getValue(), 0.0);
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model.setScale(regionUndef);
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model.setValue(1.1);
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assertEquals(1.1, model.getValue(), 0.0);
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}
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}

‎demoapp/src/main/java/com/androidplot/demos/TouchZoomExampleActivity.java‎

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Original file line numberDiff line numberDiff line change
@@ -31,6 +31,7 @@
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public class TouchZoomExampleActivity extends Activity {
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private static final int SERIES_SIZE = 3000;
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private static final int SERIES_ALPHA = 255;
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private static final int NUM_GRIDLINES = 5;
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private XYPlot plot;
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private PanZoom panZoom;
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private Button resetButton;
@@ -53,8 +54,14 @@ public void onClick(View view) {
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// move dynamically with the data when the users pans or zooms:
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plot.setUserDomainOrigin(0);
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plot.setUserRangeOrigin(0);
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plot.setDomainStep(StepMode.INCREMENT_BY_VAL, 500);
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plot.setRangeStep(StepMode.INCREMENT_BY_VAL, 100);
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// predefine the stepping of both axis
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// increment will be chosen from list to best fit NUM_GRIDLINES grid lines
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double[] inc_domain = new double[]{10,50,100,500};
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double[] inc_range = new double[]{1,5,10,20,50,100};
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plot.setDomainStepModel(new StepModelFit(plot.getBounds().getxRegion(),inc_domain,NUM_GRIDLINES));
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plot.setRangeStepModel( new StepModelFit(plot.getBounds().getyRegion(),inc_range,NUM_GRIDLINES));
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panSpinner = (Spinner) findViewById(R.id.pan_spinner);
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zoomSpinner = (Spinner) findViewById(R.id.zoom_spinner);

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