Inheritance diagram for com.google.appinventor.components.runtime.Canvas:

Classes
interface	ExtensionGestureDetector

class	FlingGestureListener

class	MotionEventParser

Public Member Functions
	Canvas (ComponentContainer container)

void	Initialize ()

View	getView ()

Activity	getContext ()

void	registerCustomGestureDetector (ExtensionGestureDetector detector)

void	removeCustomGestureDetector (Object detector)

boolean	ready ()

Activity	$context ()

Form	$form ()

void	$add (AndroidViewComponent component)

void	setChildWidth (AndroidViewComponent component, int width)

void	setChildHeight (AndroidViewComponent component, int height)

void	Width (int width)

void	Height (int height)

int	BackgroundColor ()

void	BackgroundColor (int argb)

String	BackgroundImage ()

void	BackgroundImage (String path)

void	BackgroundImageinBase64 (String imageUrl)

int	PaintColor ()

void	PaintColor (int argb)

float	FontSize ()

void	FontSize (float size)

float	LineWidth ()

void	LineWidth (float width)

int	TextAlignment ()

void	TextAlignment (int alignment)

boolean	ExtendMovesOutsideCanvas ()

void	ExtendMovesOutsideCanvas (boolean extend)

void	Touched (float x, float y, boolean touchedAnySprite)

void	TouchDown (float x, float y)

void	TouchUp (float x, float y)

void	Flung (float x, float y, float speed, float heading, float xvel, float yvel, boolean flungSprite)

void	Dragged (float startX, float startY, float prevX, float prevY, float currentX, float currentY, boolean draggedAnySprite)

void	Clear ()

void	DrawPoint (int x, int y)

void	DrawCircle (int centerX, int centerY, float radius, boolean fill)

void	DrawLine (int x1, int y1, int x2, int y2)

void	DrawShape (YailList pointList, boolean fill)

void	DrawArc (int left, int top, int right, int bottom, float startAngle, float sweepAngle, boolean useCenter, boolean fill)

void	DrawText (String text, int x, int y)

void	DrawTextAtAngle (String text, int x, int y, float angle)

int	GetBackgroundPixelColor (int x, int y)

void	SetBackgroundPixelColor (int x, int y, @IsColor int color)

int	GetPixelColor (int x, int y)

String	Save ()

String	SaveAs (String fileName)

Public Member Functions inherited from com.google.appinventor.components.runtime.AndroidViewComponent
boolean	Visible ()

void	Visible (boolean visibility)

int	Width ()

void	WidthPercent (int pCent)

void	setLastWidth (int width)

int	getSetWidth ()

void	setLastHeight (int height)

int	getSetHeight ()

void	CopyWidth (AndroidViewComponent sourceComponent)

int	Height ()

void	HeightPercent (int pCent)

void	CopyHeight (AndroidViewComponent sourceComponent)

int	Column ()

void	Column (int column)

int	Row ()

void	Row (int row)

HandlesEventDispatching	getDispatchDelegate ()

Public Member Functions inherited from com.google.appinventor.components.runtime.ComponentContainer
int	Width ()

int	Height ()

Protected Member Functions
void	findSpriteCollisions (Sprite movedSprite)

Protected Member Functions inherited from com.google.appinventor.components.runtime.AndroidViewComponent
	AndroidViewComponent (ComponentContainer container)

Protected Member Functions inherited from com.google.appinventor.components.runtime.VisibleComponent
	VisibleComponent ()

Additional Inherited Members
Static Public Attributes inherited from com.google.appinventor.components.runtime.Component
static final String	ASSET_DIRECTORY = "component"

static final int	ALIGNMENT_NORMAL = 0

static final int	ALIGNMENT_CENTER = 1

static final int	ALIGNMENT_OPPOSITE = 2

static final int	ACCELEROMETER_SENSITIVITY_WEAK = 1

static final int	ACCELEROMETER_SENSITIVITY_MODERATE = 2

static final int	ACCELEROMETER_SENSITIVITY_STRONG = 3

static final int	BUTTON_SHAPE_DEFAULT = 0

static final int	BUTTON_SHAPE_ROUNDED = 1

static final int	BUTTON_SHAPE_RECT = 2

static final int	BUTTON_SHAPE_OVAL = 3

static final int	COLOR_NONE = 0x00FFFFFF

static final int	COLOR_BLACK = 0xFF000000

static final int	COLOR_BLUE = 0xFF0000FF

static final int	COLOR_CYAN = 0xFF00FFFF

static final int	COLOR_DKGRAY = 0xFF444444

static final int	COLOR_GRAY = 0xFF888888

static final int	COLOR_GREEN = 0xFF00FF00

static final int	COLOR_LTGRAY = 0xFFCCCCCC

static final int	COLOR_MAGENTA = 0xFFFF00FF

static final int	COLOR_ORANGE = 0xFFFFC800

static final int	COLOR_PINK = 0xFFFFAFAF

static final int	COLOR_RED = 0xFFFF0000

static final int	COLOR_WHITE = 0xFFFFFFFF

static final int	COLOR_YELLOW = 0xFFFFFF00

static final int	COLOR_DEFAULT = 0x00000000

static final String	DEFAULT_VALUE_COLOR_NONE = "&H00FFFFFF"

static final String	DEFAULT_VALUE_COLOR_BLACK = "&HFF000000"

static final String	DEFAULT_VALUE_COLOR_BLUE = "&HFF0000FF"

static final String	DEFAULT_VALUE_COLOR_CYAN = "&HFF00FFFF"

static final String	DEFAULT_VALUE_COLOR_DKGRAY = "&HFF444444"

static final String	DEFAULT_VALUE_COLOR_GRAY = "&HFF888888"

static final String	DEFAULT_VALUE_COLOR_GREEN = "&HFF00FF00"

static final String	DEFAULT_VALUE_COLOR_LTGRAY = "&HFFCCCCCC"

static final String	DEFAULT_VALUE_COLOR_MAGENTA = "&HFFFF00FF"

static final String	DEFAULT_VALUE_COLOR_ORANGE = "&HFFFFC800"

static final String	DEFAULT_VALUE_COLOR_PINK = "&HFFFFAFAF"

static final String	DEFAULT_VALUE_COLOR_RED = "&HFFFF0000"

static final String	DEFAULT_VALUE_COLOR_WHITE = "&HFFFFFFFF"

static final String	DEFAULT_VALUE_COLOR_YELLOW = "&HFFFFFF00"

static final String	DEFAULT_VALUE_COLOR_DEFAULT = "&H00000000"

static final float	FONT_DEFAULT_SIZE = 14

static final int	LAYOUT_ORIENTATION_HORIZONTAL = ComponentConstants.LAYOUT_ORIENTATION_HORIZONTAL

static final int	LAYOUT_ORIENTATION_VERTICAL = ComponentConstants.LAYOUT_ORIENTATION_VERTICAL

static final int	SCALING_SCALE_PROPORTIONALLY = 0

static final int	SCALING_SCALE_TO_FIT = 1

static final int	TYPEFACE_DEFAULT = 0

static final int	TYPEFACE_SANSSERIF = 1

static final int	TYPEFACE_SERIF = 2

static final int	TYPEFACE_MONOSPACE = 3

static final int	LENGTH_PREFERRED = -1

static final int	LENGTH_FILL_PARENT = -2

static final int	LENGTH_UNKNOWN = -3

static final int	LENGTH_PERCENT_TAG = -1000

static final int	TOAST_LENGTH_SHORT = 0

static final int	TOAST_LENGTH_LONG = 1

static final int	DIRECTION_NORTH = 1

static final int	DIRECTION_NORTHEAST = 2

static final int	DIRECTION_EAST = 3

static final int	DIRECTION_SOUTHEAST = 4

static final int	DIRECTION_SOUTH = -1

static final int	DIRECTION_SOUTHWEST = -2

static final int	DIRECTION_WEST = -3

static final int	DIRECTION_NORTHWEST = -4

static final int	DIRECTION_NONE = 0

static final int	DIRECTION_MIN = -4

static final int	DIRECTION_MAX = 4

static float	SLIDER_MIN_VALUE = 10

static float	SLIDER_MAX_VALUE = 50

static float	SLIDER_THUMB_VALUE = (SLIDER_MIN_VALUE + SLIDER_MAX_VALUE) / 2.0f

static final String	DEFAULT_VALUE_TEXT_TO_SPEECH_COUNTRY = ""

static final String	DEFAULT_VALUE_TEXT_TO_SPEECH_LANGUAGE = ""

Protected Attributes inherited from com.google.appinventor.components.runtime.AndroidViewComponent
final ComponentContainer	container

Detailed Description

A two-dimensional touch-sensitive rectangular panel on which drawing can be done and sprites can be moved.

The BackgroundColor(), PaintColor(), BackgroundImage(), Width(), and Height() of the Canvas can be set in either the Designer or in the Blocks Editor. The Width and Height are measured in pixels and must be positive.

Any location on the Canvas can be specified as a pair of (X, Y) values, where

X is the number of pixels away from the left edge of the Canvas
Y is the number of pixels away from the top edge of the Canvas

There are events to tell when and where a Canvas has been touched or a Sprite (ImageSprite or Ball) has been dragged. There are also methods for drawing points, lines, circles, shapes, arcs, and text.

@internaldoc

Conceptually, a sprite consists of the following layers, from back to front (with items in front being drawn on top):

background color
background image
the "drawing layer", populated through calls to DrawPoint(int,int), DrawCircle(int,int,float,boolean), DrawText(String,int,int), and DrawTextAtAngle(String,int,int,float), and SetBackgroundPixelColor(int,int,int)
the sprite layer, where sprites with higher Z values are drawn in front of (after) sprites with lower Z values.

To the user, the first three layers are all the background, in terms of the behavior of SetBackgroundPixelColor(int,int,int) and GetBackgroundPixelColor(int,int). For historical reasons, changing the background color or image clears the drawing layer.

Definition at line 132 of file Canvas.java.

Constructor & Destructor Documentation

◆ Canvas()

com.google.appinventor.components.runtime.Canvas.Canvas ( ComponentContainer container )

Definition at line 750 of file Canvas.java.

Member Function Documentation

◆ $add()

void com.google.appinventor.components.runtime.Canvas.$add ( AndroidViewComponent component )

Adds a component to a container.

After this method is finished executing, the given component's view must have LayoutParams, even if the component cannot be added to the container until later.

Parameters

component component associated with view

Implements com.google.appinventor.components.runtime.ComponentContainer.

Definition at line 882 of file Canvas.java.

◆ $context()

Activity com.google.appinventor.components.runtime.Canvas.$context ( )

Returns the activity context (which can be retrieved from the root container - aka the form).

Returns: activity context

Implements com.google.appinventor.components.runtime.ComponentContainer.

Definition at line 872 of file Canvas.java.

◆ $form()

Form com.google.appinventor.components.runtime.Canvas.$form ( )

Returns the form that ultimately contains this container.

Returns: form

Implements com.google.appinventor.components.runtime.ComponentContainer.

Definition at line 877 of file Canvas.java.

◆ BackgroundColor() [1/2]

int com.google.appinventor.components.runtime.Canvas.BackgroundColor ( )

Returns the button's background color as an alpha-red-green-blue integer, i.e.,

0xAARRGGBB

. An alpha of

00

indicates fully transparent and

FF

means opaque.

Returns: background color in the format 0xAARRGGBB, which includes alpha, red, green, and blue components

Definition at line 1021 of file Canvas.java.

◆ BackgroundColor() [2/2]

void com.google.appinventor.components.runtime.Canvas.BackgroundColor ( int argb )

Specifies the Canvas's background color as an alpha-red-green-blue integer, i.e.,

0xAARRGGBB

. An alpha of

00

indicates fully transparent and

FF

means opaque. The background color only shows if there is no background image.

Parameters

argb	background color in the format 0xAARRGGBB, which includes alpha, red, green, and blue components

Definition at line 1037 of file Canvas.java.

◆ BackgroundImage() [1/2]

String com.google.appinventor.components.runtime.Canvas.BackgroundImage ( )

Returns the path of the canvas background image.

Returns: the path of the canvas background image

Definition at line 1049 of file Canvas.java.

◆ BackgroundImage() [2/2]

void com.google.appinventor.components.runtime.Canvas.BackgroundImage ( String path )

Specifies the name of a file containing the background image for the Canvas.

@internaldoc

See MediaUtil#determineMediaSource for information about what a path can be.

Parameters

path	the path of the canvas background image

Definition at line 1065 of file Canvas.java.

◆ BackgroundImageinBase64()

void com.google.appinventor.components.runtime.Canvas.BackgroundImageinBase64 ( String imageUrl )

Specifies the backgound image in Base64 format imageUrl will be in format of: iVBORw0KG...s//f+4z/6Z @suppressdoc

Parameters

imageUrl the base64 format for an image

Definition at line 1080 of file Canvas.java.

◆ Clear()

void com.google.appinventor.components.runtime.Canvas.Clear ( )

Clears the canvas, without removing the background image, if one was provided.

Definition at line 1344 of file Canvas.java.

◆ Dragged()

void com.google.appinventor.components.runtime.Canvas.Dragged	(	float	startX,
		float	startY,
		float	prevX,
		float	prevY,
		float	currentX,
		float	currentY,
		boolean	draggedAnySprite
	)

When the user does a drag from one point (prevX, prevY) to another (x, y). The pair (startX, startY) indicates where the user first touched the screen, and "draggedAnySprite" indicates whether a sprite is being dragged.

Parameters

startX	the starting x-coordinate
startY	the starting y-coordinate
prevX	the previous x-coordinate (possibly equal to startX)
prevY	the previous y-coordinate (possibly equal to startY)
currentX	the current x-coordinate
currentY	the current y-coordinate
draggedAnySprite

Definition at line 1330 of file Canvas.java.

◆ DrawArc()

void com.google.appinventor.components.runtime.Canvas.DrawArc	(	int	left,
		int	top,
		int	right,
		int	bottom,
		float	startAngle,
		float	sweepAngle,
		boolean	useCenter,
		boolean	fill
	)

Draw an arc on Canvas, by drawing an arc from a specified oval (specified by left, top, right & bottom). Start angle is 0 when heading to the right, and increase when rotate clockwise. When useCenter is true, a sector will be drawed instead of an arc. When fill is true, a filled arc (or sector) will be drawed instead of just an outline.

Parameters

left	the left end of the oval
top	the top of the oval
right	the right end of the oval
bottom	the bottom of the oval
startAngle	the start angle of the arc, rightward as 0, clockwise as positive, in degree
sweepAngle	the sweep angle of the arc, clockwise as positive, in degree
useCenter	fill a sector instead of just an arc (when true)
fill	true for filled arc (or sector); false for outline only

Definition at line 1495 of file Canvas.java.

◆ DrawCircle()

void com.google.appinventor.components.runtime.Canvas.DrawCircle	(	int	centerX,
		int	centerY,
		float	radius,
		boolean	fill
	)

Draws a circle (filled in) with the given radius centered at the given coordinates on the Canvas.

Parameters

centerX	x-coordinate of the center of the circle
centerY	y-coordinate of the center of the circle
radius	radius of the circle
fill	true for filled circle; false for circle outline

Definition at line 1372 of file Canvas.java.

◆ DrawLine()

void com.google.appinventor.components.runtime.Canvas.DrawLine	(	int	x1,
		int	y1,
		int	x2,
		int	y2
	)

Draws a line between the given coordinates on the canvas.

Parameters

x1	x coordinate of first point
y1	y coordinate of first point
x2	x coordinate of second point
y2	y coordinate of second point

Definition at line 1391 of file Canvas.java.

◆ DrawPoint()

void com.google.appinventor.components.runtime.Canvas.DrawPoint	(	int	x,
		int	y
	)

Draws a point at the given coordinates on the canvas.

Parameters

x	x coordinate
y	y coordinate

Definition at line 1355 of file Canvas.java.

◆ DrawShape()

void com.google.appinventor.components.runtime.Canvas.DrawShape	(	YailList	pointList,
		boolean	fill
	)

Draws a shape on the canvas. pointList should be a list contains sub-lists with two number which represents a coordinate. The first point and last point does not need to be the same. e.g. ((x1 y1) (x2 y2) (x3 y3)) When fill is true, the shape will be filled.

Parameters

pointList	A list of points, should contains sub-lists with two number which represents a coordinate. The first point and last point does not need to be the same. e.g. ((x1 y1) (x2 y2) (x3 y3))
fill	true for filled shape; false for shape outline

Definition at line 1415 of file Canvas.java.

◆ DrawText()

void com.google.appinventor.components.runtime.Canvas.DrawText	(	String	text,
		int	x,
		int	y
	)

Draws the specified text relative to the specified coordinates using the values of the FontSize(float) and TextAlignment(int) properties.

Parameters

text	the text to draw
x	the x-coordinate of the origin
y	the y-coordinate of the origin

Definition at line 1518 of file Canvas.java.

◆ DrawTextAtAngle()

void com.google.appinventor.components.runtime.Canvas.DrawTextAtAngle	(	String	text,
		int	x,
		int	y,
		float	angle
	)

Draws the specified text starting at the specified coordinates at the specified angle using the values of the FontSize(float) and TextAlignment(int) properties.

Parameters

text	the text to draw
x	the x-coordinate of the origin
y	the y-coordinate of the origin
angle	the angle (in degrees) at which to draw the text

Definition at line 1538 of file Canvas.java.

◆ ExtendMovesOutsideCanvas() [1/2]

boolean com.google.appinventor.components.runtime.Canvas.ExtendMovesOutsideCanvas ( )

Definition at line 1231 of file Canvas.java.

◆ ExtendMovesOutsideCanvas() [2/2]

void com.google.appinventor.components.runtime.Canvas.ExtendMovesOutsideCanvas ( boolean extend )

@suppressdoc

Parameters

extend

Definition at line 1241 of file Canvas.java.

◆ findSpriteCollisions()

void com.google.appinventor.components.runtime.Canvas.findSpriteCollisions ( Sprite movedSprite )

protected

Checks if the given sprite now overlaps with or abuts any other sprite or has ceased to do so. If there is a sprite that is newly in collision with it, Sprite#CollidedWith(Sprite) is called for each sprite with the other sprite as an argument. If two sprites that had been in collision are no longer colliding, Sprite#NoLongerCollidingWith(Sprite) is called for each sprite with the other as an argument. Collisions are only recognized between sprites that are both com.google.appinventor.components.runtime.Sprite#Visible() and com.google.appinventor.components.runtime.Sprite#Enabled().

Parameters

movedSprite the sprite that has just changed position

Definition at line 927 of file Canvas.java.

◆ Flung()

void com.google.appinventor.components.runtime.Canvas.Flung	(	float	x,
		float	y,
		float	speed,
		float	heading,
		float	xvel,
		float	yvel,
		boolean	flungSprite
	)

When a fling gesture (quick swipe) is made on the canvas: provides the (x,y) position of the start of the fling, relative to the upper left of the canvas. Also provides the speed (pixels per millisecond) and heading (0-360 degrees) of the fling, as well as the x velocity and y velocity components of the fling's vector. The value "flungSprite" is true if a sprite was located near the the starting point of the fling gesture.

Parameters

x	x-coordinate of touched point
y	y-coordinate of touched point
speed	the speed of the fling sqrt(xspeed^2 + yspeed^2)
heading	the heading of the fling
xvel	the speed in x-direction of the fling
yvel	the speed in y-direction of the fling
flungSprite

Definition at line 1307 of file Canvas.java.

◆ FontSize() [1/2]

float com.google.appinventor.components.runtime.Canvas.FontSize ( )

Definition at line 1135 of file Canvas.java.

◆ FontSize() [2/2]

void com.google.appinventor.components.runtime.Canvas.FontSize ( float size )

Specifies the font size of text drawn on the Canvas.

Parameters

size

Definition at line 1147 of file Canvas.java.

◆ GetBackgroundPixelColor()

int com.google.appinventor.components.runtime.Canvas.GetBackgroundPixelColor	(	int	x,
		int	y
	)

Gets the color of the given pixel, ignoring sprites.

Parameters

x	the x-coordinate
y	the y-coordinate

Returns: the color at that location as an alpha-red-blue-green integer, or Component#COLOR_NONE if that point is not on this Canvas

Definition at line 1556 of file Canvas.java.

◆ getContext()

Activity com.google.appinventor.components.runtime.Canvas.getContext ( )

Definition at line 796 of file Canvas.java.

◆ GetPixelColor()

int com.google.appinventor.components.runtime.Canvas.GetPixelColor	(	int	x,
		int	y
	)

Gets the color of the given pixel, including sprites.

Parameters

x	the x-coordinate
y	the y-coordinate

Returns: the color at that location as an alpha-red-blue-green integer, or Component#COLOR_NONE if that point is not on this Canvas

Definition at line 1591 of file Canvas.java.

◆ getView()

View com.google.appinventor.components.runtime.Canvas.getView ( )

Returns the View that is displayed in the UI.

Reimplemented from com.google.appinventor.components.runtime.AndroidViewComponent.

Definition at line 792 of file Canvas.java.

◆ Height()

void com.google.appinventor.components.runtime.Canvas.Height ( int height )

Specifies the type%'s vertical height, measured in pixels.

@internaldoc The height can only be set to >0 or -1 (automatic) or -2 (fill parent) or to a value less then or equal to LENGTH_PERCENT_TAG (which is later converted to pixels.

Parameters

height

Reimplemented from com.google.appinventor.components.runtime.AndroidViewComponent.

Definition at line 997 of file Canvas.java.

◆ Initialize()

void com.google.appinventor.components.runtime.Canvas.Initialize ( )

Definition at line 773 of file Canvas.java.

◆ LineWidth() [1/2]

float com.google.appinventor.components.runtime.Canvas.LineWidth ( )

Returns the currently specified stroke width

Returns: width

Definition at line 1159 of file Canvas.java.

◆ LineWidth() [2/2]

void com.google.appinventor.components.runtime.Canvas.LineWidth ( float width )

Specifies the width of lines drawn on the Canvas.

Parameters

width

Definition at line 1171 of file Canvas.java.

◆ PaintColor() [1/2]

int com.google.appinventor.components.runtime.Canvas.PaintColor ( )

Returns the currently specified paint color as an alpha-red-green-blue integer, i.e.,

0xAARRGGBB

. An alpha of

00

indicates fully transparent and

FF

means opaque.

Returns: paint color in the format 0xAARRGGBB, which includes alpha, red, green, and blue components

Definition at line 1101 of file Canvas.java.

◆ PaintColor() [2/2]

void com.google.appinventor.components.runtime.Canvas.PaintColor ( int argb )

Specifies the paint color as an alpha-red-green-blue integer, i.e.,

0xAARRGGBB

. An alpha of

00

indicates fully transparent and

FF

means opaque.

Parameters

argb	paint color in the format 0xAARRGGBB, which includes alpha, red, green, and blue components

Definition at line 1116 of file Canvas.java.

◆ ready()

boolean com.google.appinventor.components.runtime.Canvas.ready ( )

Returns whether the layout associated with this view has been computed. If so, Width() and Height() will be properly initialized.

Returns: true

if it is safe to call Width() and {}, false otherwise

Definition at line 820 of file Canvas.java.

◆ registerCustomGestureDetector()

void com.google.appinventor.components.runtime.Canvas.registerCustomGestureDetector ( ExtensionGestureDetector detector )

Definition at line 801 of file Canvas.java.

◆ removeCustomGestureDetector()

void com.google.appinventor.components.runtime.Canvas.removeCustomGestureDetector ( Object detector )

Definition at line 806 of file Canvas.java.

◆ Save()

String com.google.appinventor.components.runtime.Canvas.Save ( )

Saves a picture of this Canvas to the device's external storage. If an error occurs, the Screen's ErrorOccurred event will be called.

Returns: the full path name of the saved file, or the empty string if the save failed

Definition at line 1608 of file Canvas.java.

◆ SaveAs()

String com.google.appinventor.components.runtime.Canvas.SaveAs ( String fileName )

Saves a picture of this Canvas to the device's external storage in the file named fileName. fileName must end with one of ".jpg", ".jpeg", or ".png" (which determines the file type: JPEG, or PNG).

Returns: the full path name of the saved file, or the empty string if the save failed

Definition at line 1637 of file Canvas.java.

◆ SetBackgroundPixelColor()

void com.google.appinventor.components.runtime.Canvas.SetBackgroundPixelColor	(	int	x,
		int	y,
		@IsColor int	color
	)

Sets the color of the given pixel. This has no effect if the coordinates are out of bounds.

Parameters

x	the x-coordinate
y	the y-coordinate
color	the color as an alpha-red-blue-green integer

Definition at line 1572 of file Canvas.java.

◆ setChildHeight()

void com.google.appinventor.components.runtime.Canvas.setChildHeight	(	AndroidViewComponent	component,
		int	height
	)

Implements com.google.appinventor.components.runtime.ComponentContainer.

Definition at line 892 of file Canvas.java.

◆ setChildWidth()

void com.google.appinventor.components.runtime.Canvas.setChildWidth	(	AndroidViewComponent	component,
		int	width
	)

Implements com.google.appinventor.components.runtime.ComponentContainer.

Definition at line 887 of file Canvas.java.

◆ TextAlignment() [1/2]

int com.google.appinventor.components.runtime.Canvas.TextAlignment ( )

Returns the alignment of the canvas's text: center, normal (starting at the specified point in drawText()), or opposite (ending at the specified point in drawText()).

Returns: one of Component#ALIGNMENT_NORMAL, Component#ALIGNMENT_CENTER or Component#ALIGNMENT_OPPOSITE

Definition at line 1191 of file Canvas.java.

◆ TextAlignment() [2/2]

void com.google.appinventor.components.runtime.Canvas.TextAlignment ( int alignment )

Specifies the alignment of the canvas's text: center, normal (starting at the specified point in DrawText or DrawTextAtAngle(String, int, int, float)), or opposite (ending at the specified point in DrawText(String, int, int) or DrawTextAtAngle(String, int, int, float)).

Parameters

alignment one of Component#ALIGNMENT_NORMAL, Component#ALIGNMENT_CENTER or Component#ALIGNMENT_OPPOSITE

Definition at line 1210 of file Canvas.java.

◆ TouchDown()

void com.google.appinventor.components.runtime.Canvas.TouchDown	(	float	x,
		float	y
	)

When the user begins touching the canvas (places finger on canvas and leaves it there): provides the (x,y) position of the touch, relative to the upper left of the canvas

Parameters

x	x-coordinate of the point that was touched
y	y-coordinate of the point that was touched

Definition at line 1271 of file Canvas.java.

◆ Touched()

void com.google.appinventor.components.runtime.Canvas.Touched	(	float	x,
		float	y,
		boolean	touchedAnySprite
	)

When the user touches the canvas and then immediately lifts finger: provides the (x,y) position of the touch, relative to the upper left of the canvas. TouchedAnySprite is true if the same touch also touched a sprite, and false otherwise.

Parameters

x	x-coordinate of the point that was touched
y	y-coordinate of the point that was touched
touchedAnySprite

Definition at line 1258 of file Canvas.java.

◆ TouchUp()

void com.google.appinventor.components.runtime.Canvas.TouchUp	(	float	x,
		float	y
	)

When the user stops touching the canvas (lifts finger after a TouchDown event): provides the (x,y) position of the touch, relative to the upper left of the canvas

Parameters

x	x-coordinate of the point that was touched
y	y-coordinate of the point that was touched

Definition at line 1284 of file Canvas.java.

◆ Width()

void com.google.appinventor.components.runtime.Canvas.Width ( int width )

Specifies the horizontal width of the type%, measured in pixels.

@internaldoc The width can only be set to >0 or -1 (automatic) or -2 (fill parent) or to a value less then or equal to LENGTH_PERCENT_TAG (which is later converted to pixels.

Parameters

width

Reimplemented from com.google.appinventor.components.runtime.AndroidViewComponent.

Definition at line 973 of file Canvas.java.

The documentation for this class was generated from the following file:

C:/Users/Ulli/appinventor-sources/appinventor/components/src/com/google/appinventor/components/runtime/Canvas.java

Classes

Public Member Functions

Protected Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ Canvas()

Member Function Documentation

◆ $add()

◆ $context()

◆ $form()

◆ BackgroundColor() [1/2]

◆ BackgroundColor() [2/2]

◆ BackgroundImage() [1/2]

◆ BackgroundImage() [2/2]

◆ BackgroundImageinBase64()

◆ Clear()

◆ Dragged()

◆ DrawArc()

◆ DrawCircle()

◆ DrawLine()

◆ DrawPoint()

◆ DrawShape()

◆ DrawText()

◆ DrawTextAtAngle()

◆ ExtendMovesOutsideCanvas() [1/2]

◆ ExtendMovesOutsideCanvas() [2/2]

◆ findSpriteCollisions()

◆ Flung()

◆ FontSize() [1/2]

◆ FontSize() [2/2]

◆ GetBackgroundPixelColor()

◆ getContext()

◆ GetPixelColor()

◆ getView()

◆ Height()

◆ Initialize()

◆ LineWidth() [1/2]

◆ LineWidth() [2/2]

◆ PaintColor() [1/2]

◆ PaintColor() [2/2]

◆ ready()

◆ registerCustomGestureDetector()

◆ removeCustomGestureDetector()

◆ Save()

◆ SaveAs()

◆ SetBackgroundPixelColor()

◆ setChildHeight()

◆ setChildWidth()

◆ TextAlignment() [1/2]

◆ TextAlignment() [2/2]

◆ TouchDown()

◆ Touched()

◆ TouchUp()

◆ Width()