eu.webtoolkit.jwt
Interface WPaintDevice

All Known Subinterfaces:

WVectorImage

All Known Implementing Classes:

WCanvasPaintDevice, WRasterPaintDevice, WSvgImage, WVmlImage

public interface WPaintDevice

The abstract base class for a paint device.

A WPaintDevice is a device on which may be painted using a WPainter. You should never paint directly on a paint device.

The device defines the size of the drawing area, using getWidth() and getHeight(). These dimensions must be defined in pixel units. In the future, additional information will be included to convert these pixel units to lengths (using DPI information).

You should reimplement this class if you wish to extend the JWt paint system to paint on other devices than the ones provided by the library.

Note: this interface is subject to changes to increase optimization possibilities for the painting using different devices.

See Also:

WPainter

Nested Class Summary

static class	WPaintDevice.ChangeFlag Enumeration to communicate painter state changes.
static class	WPaintDevice.FeatureFlag Enumeration to indicate paint device features.

Method Summary

void	done() Finishes painting on the device.
void	drawArc(WRectF rect, double startAngle, double spanAngle) Draws an arc.
void	drawImage(WRectF rect, java.lang.String imageUri, int imgWidth, int imgHeight, WRectF sourceRect) Draws an image.
void	drawLine(double x1, double y1, double x2, double y2) Draws a line.
void	drawPath(WPainterPath path) Draws a path.
void	drawText(WRectF rect, java.util.EnumSet<AlignmentFlag> alignmentFlags, TextFlag textFlag, java.lang.CharSequence text) Draws text.
java.util.EnumSet<WPaintDevice.FeatureFlag>	getFeatures() Returns device features.
WFontMetrics	getFontMetrics() Returns font metrics.
WLength	getHeight() Returns the device height.
WPainter	getPainter() Returns the painter that is currently painting on the device.
WLength	getWidth() Returns the device width.
void	init() Initializes the device for painting.
boolean	isPaintActive() Returns whether painting is active.
WTextItem	measureText(java.lang.CharSequence text) Measures rendered text size.
WTextItem	measureText(java.lang.CharSequence text, double maxWidth) Measures rendered text size.
WTextItem	measureText(java.lang.CharSequence text, double maxWidth, boolean wordWrap) Measures rendered text size.
void	setChanged(java.util.EnumSet<WPaintDevice.ChangeFlag> flags) Indicates changes in painter state.
void	setChanged(WPaintDevice.ChangeFlag flag, WPaintDevice.ChangeFlag... flags) Indicates changes in painter state.
void	setPainter(WPainter painter) Sets the painter.

Method Detail

getFeatures

java.util.EnumSet<WPaintDevice.FeatureFlag> getFeatures()

Returns device features.

getWidth

WLength getWidth()

Returns the device width.

The device width, in pixels, establishes the width of the device coordinate system.

getHeight

WLength getHeight()

Returns the device height.

The device height, in pixels, establishes the height of the device coordinate system.

setChanged

void setChanged(java.util.EnumSet<WPaintDevice.ChangeFlag> flags)

Indicates changes in painter state.

The flags argument is the logical OR of one or more change flags.

See Also:

WPaintDevice.ChangeFlag

setChanged

void setChanged(WPaintDevice.ChangeFlag flag,
                WPaintDevice.ChangeFlag... flags)

Indicates changes in painter state.

Calls setChanged(EnumSet.of(flag, flags))

drawArc

void drawArc(WRectF rect,
             double startAngle,
             double spanAngle)

Draws an arc.

The arc is defined as in WPainter#drawArc()

The arc must be stroked, filled, and transformed using the current painter settings.

drawImage

void drawImage(WRectF rect,
               java.lang.String imageUri,
               int imgWidth,
               int imgHeight,
               WRectF sourceRect)

Draws an image.

Draws sourceRect from the image with URL imageUri and original dimensions imgWidth and imgHeight to the location, into the rectangle defined by rect.

The image is transformed using the current painter settings.

drawLine

void drawLine(double x1,
              double y1,
              double x2,
              double y2)

Draws a line.

The line must be stroked and transformed using the current painter settings.

drawPath

void drawPath(WPainterPath path)

Draws a path.

The path must be stroked, filled, and transformed using the current painter settings.

drawText

void drawText(WRectF rect,
              java.util.EnumSet<AlignmentFlag> alignmentFlags,
              TextFlag textFlag,
              java.lang.CharSequence text)

Draws text.

The text must be rendered, stroked and transformed using the current painter settings.

measureText

WTextItem measureText(java.lang.CharSequence text,
                      double maxWidth,
                      boolean wordWrap)

Measures rendered text size.

Returns the bounding rect of the given text when rendered using the current font.

If maxWidth != -1, then the text is truncated to fit in the width.

If wordWrap = true then text is truncated only at word boundaries. Note that in this case the whitespace at the truncated position is included in the text but not accounted for by the returned width (since usually you will not render the whitespace at the end of a line).

Throws a std::logic_error if the underlying device does not provide font metrics.

measureText

WTextItem measureText(java.lang.CharSequence text)

Measures rendered text size.

Returns measureText(text, - 1, false)

measureText

WTextItem measureText(java.lang.CharSequence text,
                      double maxWidth)

Measures rendered text size.

Returns measureText(text, maxWidth, false)

getFontMetrics

WFontMetrics getFontMetrics()

Returns font metrics.

This returns font metrics for the current font.

Throws a std::logic_error if the underlying device does not provide font metrics.

init

void init()

Initializes the device for painting.

This method is called when a WPainter starts painting.

See Also:

WPainter.begin(WPaintDevice device), getPainter()

done

void done()

Finishes painting on the device.

This method is called when a WPainter stopped painting.

See Also:

WPainter.end()

isPaintActive

boolean isPaintActive()

Returns whether painting is active.

See Also:

init(), getPainter()

getPainter

WPainter getPainter()

Returns the painter that is currently painting on the device.

See Also:

init()

setPainter

void setPainter(WPainter painter)

Sets the painter.