ZoomableImageView (Docs - TinyWeatherForecastGermany

java.lang.Object
- de.kaffeemitkoffein.tinyweatherforecastgermany.ZoomableImageView

```
public class ZoomableImageView
extends java.lang.Object
```
ZoomableImageView is a simple class that enhances an ImageView with the capability to zoom in and out.
Author:
Pawel Dube
Requirements and limitations:
- the imageview has to be populated with a bitmap. Other content will not work.
- WIDTH AND HEIGHT OF THE IMAGEVIEW MUST BE SET TO "MATCH_PARENT". When set to "wrap_content", the view will shrink when the bitmap inside the view shrinks due to zooming!
Gestures:
this class catches the usual "zoom in" and "zoom out" gestures:
- zoom in = move two pointers (e.g. two fingers) away from each other while touching the screen
- zoom out = move two pointers (e.g. two fingers) closer to each other while touching the screen
moving one pointer (e.g. one finger) while touching the screen moves the scaled bitmap within the imageview

Notes:
- this class always "consumes" the provided motionEvent, because the underlying ScaleGestureDetector does so. Therefore, there are NEVER any "unused" events after this class has been called. However, this is not a limitation, see example how to use.
How to use:
1. create an instance of ZoomableImageView providing Context, the imageview and the bitmap,
2. and optionally override "onGestureFinished" to catch the results once a gesture is done. If you do not need to further react after a zoom/move gesture, you can skip this.
3. Register an OnTouchListerner and handle over the motionEvent to the ZoomableImageView.
That's all.

mapImageView = (ImageView) findViewById(R.id.map); zoomableImageView = new ZoomableImageView(getApplicationContext(),mapImageView,BitmapFactory.decodeResource(getResources(),R.drawable.germany_nc,null)){

Nested Class Summary

Nested Classes
Modifier and Type Class Description

static class ZoomableImageView.SPRITEFIXPOINT
Static class that holds values how to fix a sprite to the underlying bitmap.

Nested Classes
Modifier and Type	Class	Description
`static class`	`ZoomableImageView.SPRITEFIXPOINT`	Static class that holds values how to fix a sprite to the underlying bitmap.

Field Summary

Fields
Modifier and Type	Field	Description
`float`	`lastPressX`
`float`	`lastPressY`
`float`	`maxScaleRange`	Default min.
`float`	`minScaleRange`	Default max.
`float`	`scaleFactor`	The current zoom: 1 = no zoom, values below 1 mean the bitmap is zoomed in (enlarged) values above 1 mean the bitmap is zoomed out (shrunk). Values above 1 are discouraged and may lead to unexpected behaviour of the imageview/bitmap.
`ScaleGestureDetector`	`scaleGestureDetector`
`static java.lang.String`	`STATE_SCALEFACTOR`
`static java.lang.String`	`STATE_XFOCUS`
`static java.lang.String`	`STATE_YFOCUS`
`RectF`	`temporaryVisibleArea`	Holds the borders of the visible area of the bimap.
`float`	`xFocus`	The current focus (=center) visible.
`float`	`yFocus`
`de.kaffeemitkoffein.tinyweatherforecastgermany.ZoomableImageView.ZoomGestureListener`	`zoomGestureListener`

Constructor Summary

Constructors
Constructor	Description
`ZoomableImageView(Context context, ImageView imageView, Bitmap bitmap_src)`	Initializes this class.
`ZoomableImageView(Context context, ImageView imageView, Bitmap bitmap_src, boolean fillViewPort)`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`int`	`addSpite(Bitmap bitmap, float x, float y, int fixpoint, java.lang.Float sf)`	Sprite concept: a "sprite" is a small bitmap/icon that is fixed to an absolute position on top of the underlying bitmap.
`float`	`getRelativeXFocus()`	Returns the current focus as a relative position, returns a value between 0 (=left border of the bitmap) and 1 (=right border of the bitmap).
`float`	`getRelativeYFocus()`	Returns the current focus as a relative position, returns a value between 0 (=left top of the bitmap) and 1 (=bottom of the bitmap).
`float`	`getXFocus()`	Returns the absolute focus x coordinate in pixels.
`float`	`getYFocus()`	Returns the absolute focus y coordinate in pixels.
`void`	`onGestureFinished(float scaleFactor, float lastPressX, float lastPressY, float xFocus, float yFocus, float xFocusRelative, float yFocusRelative, RectF currentlyVisibleArea)`	Always called when a gesture (zoom or movement) finished. Override this method to do something once a zoom / movement inside the imageview finished. The focus is the visible center coordinate.
`boolean`	`onTouchEvent(MotionEvent motionEvent)`	Use this method to supply all motionEvents from the imageview to this class.
`void`	`redrawBitmap()`	Redraws the bitmap inside the imageview.
`void`	`restoreZoomViewState(Bundle zoomViewState)`
`Bundle`	`saveZoomViewState()`
`void`	`setScaleRange(float min, float max)`	Optional method to set the min and max scale range. Example: setScaleRange(0.25,1); sets a maximum zoom in of 4x and a maximum zoom out to the original size.
`void`	`updateBitmap(Bitmap newbitmap)`	Updates the bitmap with a new one.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - scaleFactor
```
public float scaleFactor
```
    The current zoom:
    1 = no zoom,
    values below 1 mean the bitmap is zoomed in (enlarged)
    values above 1 mean the bitmap is zoomed out (shrunk).
    Values above 1 are discouraged and may lead to unexpected behaviour of the imageview/bitmap.
    
    Notice: this value is only accurate once a scale gesture finished. During a scale gesture, it holds the scale factor from the beginning of the gesture. In other words: it is updated at the end of the gesture, and not while a gesture is being performed.
    
    Override onGestureFinished to get the results of a gesture.
  - xFocus
```
public float xFocus
```
    The current focus (=center) visible. Both variables refer to the x/y coordinates of the underlying bitmap.
  - yFocus
```
public float yFocus
```
  - minScaleRange
```
public float minScaleRange
```
    Default max. zoom factor, 0.25f = 4x zoom.
  - maxScaleRange
```
public float maxScaleRange
```
    Default min. zoom factor, values above 1 are discouraged.
  - temporaryVisibleArea
```
public RectF temporaryVisibleArea
```
    Holds the borders of the visible area of the bimap. May be null before first gestures.
  - lastPressX
```
public float lastPressX
```
  - lastPressY
```
public float lastPressY
```
  - zoomGestureListener
```
public de.kaffeemitkoffein.tinyweatherforecastgermany.ZoomableImageView.ZoomGestureListener zoomGestureListener
```
  - scaleGestureDetector
```
public ScaleGestureDetector scaleGestureDetector
```
  - STATE_SCALEFACTOR
```
public static final java.lang.String STATE_SCALEFACTOR
```
    See Also:
    
    Constant Field Values
  - STATE_XFOCUS
```
public static final java.lang.String STATE_XFOCUS
```
    See Also:
    
    Constant Field Values
  - STATE_YFOCUS
```
public static final java.lang.String STATE_YFOCUS
```
    See Also:
    
    Constant Field Values
- Constructor Detail
  - ZoomableImageView
```
public ZoomableImageView(Context context,
                         ImageView imageView,
                         Bitmap bitmap_src)
```
    Initializes this class. Values must not be null.
    
    Parameters:
    
    context - the application context
    
    imageView - the imageview
    
    bitmap_src - the bitmap to be used in the imageview
  - ZoomableImageView
```
public ZoomableImageView(Context context,
                         ImageView imageView,
                         Bitmap bitmap_src,
                         boolean fillViewPort)
```
- Method Detail
  - setScaleRange
```
public void setScaleRange(float min,
                          float max)
```
    Optional method to set the min and max scale range.
    Example: setScaleRange(0.25,1); sets a maximum zoom in of 4x and a maximum zoom out to the original size.
    
    Parameters:
    
    min - the max. zoom, must be lower than max (e.g. 0.25 means a max. zoom of 4x).
    
    max - the min. zoom, typically 1 (original size). Values above 1 are discouraged.
  - updateBitmap
```
public void updateBitmap(Bitmap newbitmap)
```
    Updates the bitmap with a new one. If the old and new bitmap have the same width and height, the current zoom values and the focus are preserved.
    
    Parameters:
    
    newbitmap - the new bitmap, must not be null
  - addSpite
```
public int addSpite(Bitmap bitmap,
                    float x,
                    float y,
                    int fixpoint,
                    java.lang.Float sf)
```
    Sprite concept: a "sprite" is a small bitmap/icon that is fixed to an absolute position on top of the underlying bitmap. When the underlying bitmap gets zoomed in or out, the sprite does NOT zoom but always keeps the same size. It remains at the same (relative) position fixed to the underlying bitmap. Got it? Adds a sprite.
    
    Parameters:
    
    bitmap - the bitmap holding the sprite. May not be null.
    
    x - x-position (on the underlying bitmap) where to fix the sprite
    
    y - y-position (on the underlying bitmap) where to fix the sprite
    
    fixpoint - how to fix the sprite, see SPRITEFIXPOINT class
    
    Returns:
    
    number of the sprite
  - onGestureFinished
```
public void onGestureFinished(float scaleFactor,
                              float lastPressX,
                              float lastPressY,
                              float xFocus,
                              float yFocus,
                              float xFocusRelative,
                              float yFocusRelative,
                              RectF currentlyVisibleArea)
```
    Always called when a gesture (zoom or movement) finished.
    Override this method to do something once a zoom / movement inside the imageview finished.
    The focus is the visible center coordinate.
    
    Parameters:
    
    scaleFactor - the current scale factor
    
    lastPressX - the absolute x of last pointer/touch, reference is the whole bitmap
    
    lastPressY - the absolute y of last pointer/touch, reference is the whole bitmap
    
    xFocus - the absolute x focus in pixels, reference is the whole bitmap
    
    yFocus - the absolute y focus in pixels, reference is the whole bitmap
    
    xFocusRelative - the relative x focus (0 <= xFocusRelative <= 1), reference is the whole bitmap
    
    yFocusRelative - the relative y focus (0 <= yFocusRelative <= 1), reference is the whole bitmap
    
    currentlyVisibleArea - rectangle holding the coordinates of the visible area in pixels
  - getRelativeXFocus
```
public float getRelativeXFocus()
```
    Returns the current focus as a relative position, returns a value between 0 (=left border of the bitmap) and 1 (=right border of the bitmap). The position refers to the bitmap.
    The focus is the visible center coordinate.
    
    Returns:
    
    the relative x coordinate of the focus, 0 <= x <= 1
  - getRelativeYFocus
```
public float getRelativeYFocus()
```
    Returns the current focus as a relative position, returns a value between 0 (=left top of the bitmap) and 1 (=bottom of the bitmap). The position refers to the bitmap.
    The focus is the visible center coordinate.
    
    Returns:
    
    the relative y coordinate of the focus, 0 <= y <= 1
  - getXFocus
```
public float getXFocus()
```
    Returns the absolute focus x coordinate in pixels. The coordinate refers to the bitmap size in pixels.
    The focus is the visible center coordinate.
    
    Returns:
    
    absolute x coordinate
  - getYFocus
```
public float getYFocus()
```
    Returns the absolute focus y coordinate in pixels. The coordinate refers to the bitmap size in pixels.
    The focus is the visible center coordinate.
    
    Returns:
    
    absolute y coordinate
  - onTouchEvent
```
public boolean onTouchEvent(MotionEvent motionEvent)
```
    Use this method to supply all motionEvents from the imageview to this class. This is typically called from an OnTouchListener that is attached to the imageview. See example above.
    
    Parameters:
    
    motionEvent -
    
    Returns:
    
    if the motionEvent was used, always returns TRUE.
  - redrawBitmap
```
public void redrawBitmap()
```
    Redraws the bitmap inside the imageview. Uses the currently set scale factor.
  - saveZoomViewState
```
public Bundle saveZoomViewState()
```
  - restoreZoomViewState
```
public void restoreZoomViewState(Bundle zoomViewState)
```

Class ZoomableImageView

Requirements and limitations:

Gestures:

Notes:

How to use:

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

scaleFactor

xFocus

yFocus

minScaleRange

maxScaleRange

temporaryVisibleArea

lastPressX

lastPressY

zoomGestureListener

scaleGestureDetector

STATE_SCALEFACTOR

STATE_XFOCUS

STATE_YFOCUS

Constructor Detail

ZoomableImageView

ZoomableImageView

Method Detail

setScaleRange

updateBitmap

addSpite

onGestureFinished

getRelativeXFocus

getRelativeYFocus

getXFocus

getYFocus

onTouchEvent

redrawBitmap

saveZoomViewState

restoreZoomViewState