Add gradients support (close #1)

README.md

@@ -32,6 +32,9 @@ Simple but customizable view for displaying progress
 ##### With background filling enabled/disabled
 <img src="art/background-filling-1.png" width="30%" /> <img src="art/background-filling-2.png" width="30%" /> <img src="art/background-filling-3.png" width="30%" />
 
+##### With gradients [linear, sweep and radial] (details [here](#gradients))
+<img src="art/gradient_linear.png" width="30%" /> <img src="art/gradient_sweep.png" width="30%" /> <img src="art/gradient_radial.png" width="30%" />
+
 
 ## How to use
 
@@ -58,7 +61,9 @@ Add view to your layout:
         app:startAngle="270"
         app:textColor="#fffc59"
         app:textSize="14sp"
-        app:fillBackground="false" />
+        app:fillBackground="false"
+        app:gradientType="linear"
+        app:gradientEndColor="@color/colorAccent" />
 ```
 
 Since all attributes have default values, you can specify none of them. Thus following code also works:
@@ -106,6 +111,8 @@ circularProgress.getMaxProgress() // returns 10000
 |  Progress cap                                                                                                                                       | `app:progressCap`                    | setter: `setProgressStrokeCap(cap)`<br/>getter: `getProgressStrokeCap()`                                                                                                                 | `CAP_ROUND`                   |
 |  Progress animation                                                                                                                                 | `app:enableProgressAnimation`        | setter: `setAnimationEnabled(enableAnimation)`<br/>getter: `isAnimationEnabled()`                                                                                                        | `true`                        |
 |  Whether to fill background with progress background color                                                                                          | `app:fillBackground`                 | setter: `setFillBackgroundEnabled(enable)`<br/>getter: `isFillBackgroundEnabled()`                                                                                                       | `false`                       |
+|  Gradient type                                                                                                                                      | `app:gradientType`                   | setter: `setGradient(type, color)`<br/>getter: `getGradientType()`                                                                                                                       | `no_gradient`                 |
+|  End color of a gradient                                                                                                                            | `app:gradientEndColor`               | -                                                                                                                                                                                        | -                             |
 
 ---
 
@@ -208,6 +215,38 @@ circularProgress.setInterpolator(new LinearInterpolator());
 
 ---
 
+#### Gradients
+`CircularProgressIndicator` supports 3 types of gradient:
+- Linear
+- Radial (doesn't look really good)
+- Sweep
+
+They can be setup using attribute `app:gradientType"` that accepts 4 values:
+- `linear`
+- `radial`
+- `sweep`
+- `no_gradient`- default one, can also be used to remove gradient
+You also must specify end color using `app:gradientEndColor="color|reference"` attribute.
+
+Or you can set it in code:
+```java
+int endColor = Color.MAGENTA;
+
+/* Must be one of:
+*  - LINEAR_GRADIENT 
+*  - RADIAL_GRADIENT 
+*  - SWEEP_GRADIENT 
+*  - NO_GRADIENT
+* */
+int gradientType = CircularProgressIndicator.LINEAR_GRADIENT;
+
+circularProgress.setGradient(gradientType, endColor);
+
+circularProgress.getGradientType(); //returns LINEAR_GRADIENT
+```
+
+---
+
 ### Download using Gradle
 
 Add this in your root `build.gradle` at the end of `repositories` in `allprojects` section:

circularprogressindicator/src/main/java/antonkozyriatskyi/circularprogressindicator/CircularProgressIndicator.java

@@ -9,9 +9,14 @@
 import android.content.res.TypedArray;
 import android.graphics.Canvas;
 import android.graphics.Color;
+import android.graphics.LinearGradient;
+import android.graphics.Matrix;
 import android.graphics.Paint;
+import android.graphics.RadialGradient;
 import android.graphics.Rect;
 import android.graphics.RectF;
+import android.graphics.Shader;
+import android.graphics.SweepGradient;
 import android.os.Build;
 import android.support.annotation.ColorInt;
 import android.support.annotation.Dimension;
@@ -43,6 +48,11 @@ public class CircularProgressIndicator extends View {
     public static final int CAP_ROUND = 0;
     public static final int CAP_BUTT = 1;
 
+    public static final int NO_GRADIENT = 0;
+    public static final int LINEAR_GRADIENT = 1;
+    public static final int RADIAL_GRADIENT = 2;
+    public static final int SWEEP_GRADIENT = 3;
+
     private static final int DEFAULT_PROGRESS_START_ANGLE = 270;
     private static final int ANGLE_START_PROGRESS_BACKGROUND = 0;
     private static final int ANGLE_END_PROGRESS_BACKGROUND = 360;
@@ -170,6 +180,22 @@ private void init(@NonNull Context context, @Nullable AttributeSet attrs) {
 
             reformatProgressText();
 
+            final int gradientType = a.getColor(R.styleable.CircularProgressIndicator_gradientType, 0);
+            if (gradientType != NO_GRADIENT) {
+                final int gradientColorEnd = a.getColor(R.styleable.CircularProgressIndicator_gradientEndColor, -1);
+
+                if (gradientColorEnd == -1) {
+                    throw new IllegalArgumentException("did you forget to specify gradientColorEnd?");
+                }
+
+                post(new Runnable() {
+                    @Override
+                    public void run() {
+                        setGradient(gradientType, gradientColorEnd);
+                    }
+                });
+            }
+
             a.recycle();
         }
 
@@ -269,6 +295,11 @@ protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
     @Override
     protected void onSizeChanged(int w, int h, int oldw, int oldh) {
         calculateBounds(w, h);
+
+        Shader shader = progressPaint.getShader();
+        if (shader instanceof RadialGradient) {
+            RadialGradient gradient = (RadialGradient) shader;
+        }
     }
 
     private void calculateBounds(int w, int h) {
@@ -674,6 +705,54 @@ public Interpolator getInterpolator() {
         return animationInterpolator;
     }
 
+    public void setGradient(@GradientType int type, @ColorInt int endColor) {
+        Shader gradient = null;
+
+        float cx = getWidth() / 2f;
+        float cy = getHeight() / 2f;
+
+        int startColor = progressPaint.getColor();
+
+        switch (type) {
+            case LINEAR_GRADIENT:
+                gradient = new LinearGradient(0f, 0f, getWidth(), getHeight(), startColor, endColor, Shader.TileMode.CLAMP);
+                break;
+            case RADIAL_GRADIENT:
+                gradient = new RadialGradient(cx, cy, cx, startColor, endColor, Shader.TileMode.MIRROR);
+                break;
+            case SWEEP_GRADIENT:
+                gradient = new SweepGradient(cx, cy, new int[]{startColor, endColor}, null);
+                break;
+        }
+
+        if (gradient != null) {
+            Matrix matrix = new Matrix();
+            matrix.postRotate(startAngle, cx, cy);
+            gradient.setLocalMatrix(matrix);
+        }
+
+        progressPaint.setShader(gradient);
+
+        invalidate();
+    }
+
+    @GradientType
+    public int getGradientType() {
+        Shader shader = progressPaint.getShader();
+
+        int type = NO_GRADIENT;
+
+        if (shader instanceof LinearGradient) {
+            type = LINEAR_GRADIENT;
+        } else if (shader instanceof RadialGradient) {
+            type = RADIAL_GRADIENT;
+        } else if (shader instanceof SweepGradient) {
+            type = SWEEP_GRADIENT;
+        }
+
+        return type;
+    }
+
     @Retention(RetentionPolicy.SOURCE)
     @IntDef({DIRECTION_CLOCKWISE, DIRECTION_COUNTERCLOCKWISE})
     public @interface Direction {
@@ -684,6 +763,11 @@ public Interpolator getInterpolator() {
     public @interface Cap {
     }
 
+    @Retention(RetentionPolicy.SOURCE)
+    @IntDef({NO_GRADIENT, LINEAR_GRADIENT, RADIAL_GRADIENT, SWEEP_GRADIENT})
+    public @interface GradientType {
+    }
+
     public interface ProgressTextAdapter {
 
         @NonNull

circularprogressindicator/src/main/res/values/attrs.xml

@@ -32,6 +32,14 @@
 
         <attr name="fillBackground" format="boolean" />
 
+        <attr name="gradientEndColor" format="color|reference"/>
+        <attr name="gradientType" format="enum">
+            <enum name="no_gradient" value="0"/>
+            <enum name="linear" value="1"/>
+            <enum name="radial" value="2"/>
+            <enum name="sweep" value="3"/>
+        </attr>
+
     </declare-styleable>
 
 </resources>

example/src/main/java/antonkozyriatskyi/circularprogressindicatorexample/MainActivity.java

@@ -5,13 +5,19 @@
 import android.support.v7.app.AppCompatActivity;
 import android.util.Log;
 import android.view.View;
+import android.widget.AdapterView;
 import android.widget.Button;
 import android.widget.CheckBox;
 import android.widget.CompoundButton;
 import android.widget.RadioGroup;
 import android.widget.SeekBar;
+import android.widget.SimpleAdapter;
+import android.widget.Spinner;
 import android.widget.Switch;
 
+import java.util.ArrayList;
+import java.util.HashMap;
+
 import antonkozyriatskyi.circularprogressindicator.CircularProgressIndicator;
 
 
@@ -106,6 +112,50 @@ public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                 circularProgress.setAnimationEnabled(isChecked);
             }
         });
+
+        Spinner gradientType = findViewById(R.id.sp_gradient_type);
+
+        final ArrayList<HashMap<String, String>> gradients = new ArrayList<>();
+        HashMap<String, String> gradient = new HashMap<>();
+        gradient.put("type", "No gradient");
+        gradient.put("value", "0");
+        gradients.add(gradient);
+
+        gradient = new HashMap<>();
+        gradient.put("type", "Linear");
+        gradient.put("value", "1");
+        gradients.add(gradient);
+
+        gradient = new HashMap<>();
+        gradient.put("type", "Radial");
+        gradient.put("value", "2");
+        gradients.add(gradient);
+
+        gradient = new HashMap<>();
+        gradient.put("type", "Sweep");
+        gradient.put("value", "3");
+        gradients.add(gradient);
+
+
+        gradientType.setAdapter(
+                new SimpleAdapter(
+                        this,
+                        gradients,
+                        android.R.layout.simple_dropdown_item_1line,
+                        new String[]{"type"},
+                        new int[]{android.R.id.text1}
+                ));
+
+        gradientType.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
+            @Override
+            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
+                circularProgress.setGradient(Integer.parseInt(gradients.get(position).get("value")), Color.MAGENTA);
+            }
+
+            @Override
+            public void onNothingSelected(AdapterView<?> parent) {
+            }
+        });
     }
 
     @Override
@@ -154,12 +204,10 @@ public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
 
     @Override
     public void onStartTrackingTouch(SeekBar seekBar) {
-
     }
 
     @Override
     public void onStopTrackingTouch(SeekBar seekBar) {
-
     }
 
     @Override

example/src/main/res/layout/activity_main.xml

@@ -160,6 +160,11 @@
                 android:checked="true"
                 android:text="Enable animation" />
 
+            <Spinner
+                android:id="@+id/sp_gradient_type"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"/>
+
             <Button
                 android:id="@+id/btn_progress_color"
                 android:layout_width="match_parent"