de.enough.polish.ui
Interface NativeGraphics

All Known Implementing Classes:

NativeGraphicsImpl

public interface NativeGraphics

Abstracts the natively used graphics class.

When the preprocessing variable polish.build.classes.NativeGraphics is defined, that class will be used directly.

Copyright Enough Software 2010

Author:

Robert Virkus, j2mepolish@enough.de

Method Summary

void	clipRect(int x, int y, int width, int height) Intersects the current clip with the specified rectangle.
void	copyArea(int x_src, int y_src, int width, int height, int x_dest, int y_dest, int anchor) Copies the contents of a rectangular area (x_src, y_src, width, height) to a destination area, whose anchor point identified by anchor is located at (x_dest, y_dest).
void	drawArc(int x, int y, int width, int height, int startAngle, int arcAngle) Draws the outline of a circular or elliptical arc covering the specified rectangle, using the current color and stroke style.
void	drawChar(char character, int x, int y, int anchor) Draws the specified character using the current font and color.
void	drawChars(char[] data, int offset, int length, int x, int y, int anchor) Draws the specified characters using the current font and color.
void	drawImage(Image img, int x, int y, int anchor) Draws the specified image by using the anchor point.
void	drawLine(int x1, int y1, int x2, int y2) Draws a line between the coordinates (x1,y1) and (x2,y2) using the current color and stroke style.
void	drawRect(int x, int y, int width, int height) Draws the outline of the specified rectangle using the current color and stroke style.
void	drawRegion(Image src, int x_src, int y_src, int width, int height, int transform, int x_dest, int y_dest, int anchor) Copies a region of the specified source image to a location within the destination, possibly transforming (rotating and reflecting) the image data using the chosen transform function.
void	drawRGB(int[] rgbData, int offset, int scanlength, int x, int y, int width, int height, boolean processAlpha) Renders a series of device-independent RGB+transparency values in a specified region.
void	drawRoundRect(int x, int y, int width, int height, int arcWidth, int arcHeight) Draws the outline of the specified rounded corner rectangle using the current color and stroke style.
void	drawString(String str, int x, int y, int anchor) Draws the specified String using the current font and color.
void	drawSubstring(String str, int offset, int len, int x, int y, int anchor) Draws the specified String using the current font and color.
void	fillArc(int x, int y, int width, int height, int startAngle, int arcAngle) Fills a circular or elliptical arc covering the specified rectangle.
void	fillRect(int x, int y, int width, int height) Fills the specified rectangle with the current color.
void	fillRoundRect(int x, int y, int width, int height, int arcWidth, int arcHeight) Fills the specified rounded corner rectangle with the current color.
void	fillTriangle(int x1, int y1, int x2, int y2, int x3, int y3) Fills the specified triangle will the current color.
int	getBlueComponent() Gets the blue component of the current color.
int	getClipHeight() Gets the height of the current clipping area.
int	getClipWidth() Gets the width of the current clipping area.
int	getClipX() Gets the X offset of the current clipping area, relative to the coordinate system origin of this graphics context.
int	getClipY() Gets the Y offset of the current clipping area, relative to the coordinate system origin of this graphics context.
int	getColor() Gets the current color.
int	getDisplayColor(int color) Gets the color that will be displayed if the specified color is requested.
Font	getFont() Gets the current font.
int	getGrayScale() Gets the current grayscale value of the color being used for rendering operations.
int	getGreenComponent() Gets the green component of the current color.
int	getRedComponent() Gets the red component of the current color.
int	getStrokeStyle() Gets the stroke style used for drawing operations.
int	getTranslateX() Gets the X coordinate of the translated origin of this graphics context.
int	getTranslateY() Gets the Y coordinate of the translated origin of this graphics context.
void	setClip(int x, int y, int width, int height) Sets the current clip to the rectangle specified by the given coordinates.
void	setColor(int rgb) Sets the current color to the specified RGB values.
void	setColor(int red, int green, int blue) Sets the current color to the specified RGB values.
void	setFont(Font font) Sets the font for all subsequent text rendering operations.
void	setGrayScale(int value) Sets the current grayscale to be used for all subsequent rendering operations.
void	setStrokeStyle(int style) Sets the stroke style used for drawing lines, arcs, rectangles, and rounded rectangles.
void	translate(int x, int y) Translates the origin of the graphics context to the point (x, y) in the current coordinate system.

Method Detail

translate

void translate(int x,
               int y)

Translates the origin of the graphics context to the point (x, y) in the current coordinate system. All coordinates used in subsequent rendering operations on this graphics context will be relative to this new origin.

The effect of calls to translate() are cumulative. For example, calling translate(1, 2) and then translate(3, 4) results in a translation of (4, 6).

The application can set an absolute origin (ax, ay) using the following technique:

g.translate(ax - g.getTranslateX(), ay - g.getTranslateY())

Parameters:

x - - the x coordinate of the new translation origin

y - - the y coordinate of the new translation origin

See Also:

getTranslateX(), getTranslateY()

getTranslateX

int getTranslateX()

Gets the X coordinate of the translated origin of this graphics context.

Returns:

X of current origin

getTranslateY

int getTranslateY()

Gets the Y coordinate of the translated origin of this graphics context.

Returns:

Y of current origin

getColor

int getColor()

Gets the current color.

Returns:

an integer in form 0x00RRGGBB

See Also:

setColor(int, int, int)

getRedComponent

int getRedComponent()

Gets the red component of the current color.

Returns:

integer value in range 0-255

See Also:

setColor(int, int, int)

getGreenComponent

int getGreenComponent()

Gets the green component of the current color.

Returns:

integer value in range 0-255

See Also:

setColor(int, int, int)

getBlueComponent

int getBlueComponent()

Gets the blue component of the current color.

Returns:

integer value in range 0-255

See Also:

setColor(int, int, int)

getGrayScale

int getGrayScale()

Gets the current grayscale value of the color being used for rendering operations. If the color was set by setGrayScale(), that value is simply returned. If the color was set by one of the methods that allows setting of the red, green, and blue components, the value returned is computed from the RGB color components (possibly in a device-specific fashion) that best approximates the brightness of that color.

Returns:

integer value in range 0-255

See Also:

setGrayScale(int)

setColor

void setColor(int red,
              int green,
              int blue)

Sets the current color to the specified RGB values. All subsequent rendering operations will use this specified color.

Parameters:

red - - the red component of the color being set in range 0-255

green - - the green component of the color being set in range 0-255

blue - - the blue component of the color being set in range 0-255

Throws:

IllegalArgumentException - - if any of the color components are outside of range 0-255

See Also:

getColor()

setColor

void setColor(int rgb)

Sets the current color to the specified RGB values. All subsequent rendering operations will use this specified color. The RGB value passed in is interpreted with the least significant eight bits giving the blue component, the next eight more significant bits giving the green component, and the next eight more significant bits giving the red component. That is to say, the color component is specified in the form of 0x00RRGGBB. The high order byte of this value is ignored.

Parameters:

rgb - - the color being set

See Also:

getColor()

setGrayScale

void setGrayScale(int value)

Sets the current grayscale to be used for all subsequent rendering operations. For monochrome displays, the behavior is clear. For color displays, this sets the color for all subsequent drawing operations to be a gray color equivalent to the value passed in. The value must be in the range 0-255.

Parameters:

value - - the desired grayscale value

Throws:

IllegalArgumentException - - if the gray value is out of range

See Also:

getGrayScale()

getFont

Font getFont()

Gets the current font.

Returns:

current font

See Also:

Font, setFont(Font)

setStrokeStyle

void setStrokeStyle(int style)

Sets the stroke style used for drawing lines, arcs, rectangles, and rounded rectangles. This does not affect fill, text, and image operations.

Parameters:

style - - can be SOLID or DOTTED

Throws:

IllegalArgumentException - - if the style is illegal

See Also:

getStrokeStyle()

getStrokeStyle

int getStrokeStyle()

Gets the stroke style used for drawing operations.

Returns:

stroke style, SOLID or DOTTED

See Also:

setStrokeStyle(int)

setFont

void setFont(Font font)

Sets the font for all subsequent text rendering operations. If font is null, it is equivalent to setFont(Font.getDefaultFont()).

Parameters:

font - - the specified font

See Also:

Font, getFont(), drawString(java.lang.String, int, int, int), drawChars(char[], int, int, int, int, int)

getClipX

int getClipX()

Gets the X offset of the current clipping area, relative to the coordinate system origin of this graphics context. Separating the getClip operation into two methods returning integers is more performance and memory efficient than one getClip() call returning an object.

Returns:

X offset of the current clipping area

See Also:

clipRect(int, int, int, int), setClip(int, int, int, int)

getClipY

int getClipY()

Gets the Y offset of the current clipping area, relative to the coordinate system origin of this graphics context. Separating the getClip operation into two methods returning integers is more performance and memory efficient than one getClip() call returning an object.

Returns:

Y offset of the current clipping area

See Also:

clipRect(int, int, int, int), setClip(int, int, int, int)

getClipWidth

int getClipWidth()

Gets the width of the current clipping area.

Returns:

width of the current clipping area.

See Also:

clipRect(int, int, int, int), setClip(int, int, int, int)

getClipHeight

int getClipHeight()

Gets the height of the current clipping area.

Returns:

height of the current clipping area.

See Also:

clipRect(int, int, int, int), setClip(int, int, int, int)

clipRect

void clipRect(int x,
              int y,
              int width,
              int height)

Intersects the current clip with the specified rectangle. The resulting clipping area is the intersection of the current clipping area and the specified rectangle. This method can only be used to make the current clip smaller. To set the current clip larger, use the setClip method. Rendering operations have no effect outside of the clipping area.

Parameters:

x - - the x coordinate of the rectangle to intersect the clip with

y - - the y coordinate of the rectangle to intersect the clip with

width - - the width of the rectangle to intersect the clip with

height - - the height of the rectangle to intersect the clip with

See Also:

setClip(int, int, int, int)

setClip

void setClip(int x,
             int y,
             int width,
             int height)

Sets the current clip to the rectangle specified by the given coordinates. Rendering operations have no effect outside of the clipping area.

Parameters:

x - - the x coordinate of the new clip rectangle

y - - the y coordinate of the new clip rectangle

width - - the width of the new clip rectangle

height - - the height of the new clip rectangle

See Also:

clipRect(int, int, int, int)

drawLine

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

Draws a line between the coordinates (x1,y1) and (x2,y2) using the current color and stroke style.

Parameters:

x1 - - the x coordinate of the start of the line

y1 - - the y coordinate of the start of the line

x2 - - the x coordinate of the end of the line

y2 - - the y coordinate of the end of the line

fillRect

void fillRect(int x,
              int y,
              int width,
              int height)

Fills the specified rectangle with the current color. If either width or height is zero or less, nothing is drawn.

Parameters:

x - - the x coordinate of the rectangle to be filled

y - - the y coordinate of the rectangle to be filled

width - - the width of the rectangle to be filled

height - - the height of the rectangle to be filled

See Also:

drawRect(int, int, int, int)

drawRect

void drawRect(int x,
              int y,
              int width,
              int height)

Draws the outline of the specified rectangle using the current color and stroke style. The resulting rectangle will cover an area (width + 1) pixels wide by (height + 1) pixels tall. If either width or height is less than zero, nothing is drawn.

Parameters:

x - - the x coordinate of the rectangle to be drawn

y - - the y coordinate of the rectangle to be drawn

width - - the width of the rectangle to be drawn

height - - the height of the rectangle to be drawn

See Also:

fillRect(int, int, int, int)

drawRegion

void drawRegion(Image src,
                int x_src,
                int y_src,
                int width,
                int height,
                int transform,
                int x_dest,
                int y_dest,
                int anchor)

Copies a region of the specified source image to a location within the destination, possibly transforming (rotating and reflecting) the image data using the chosen transform function.

The destination, if it is an image, must not be the same image as the source image. If it is, an exception is thrown. This restriction is present in order to avoid ill-defined behaviors that might occur if overlapped, transformed copies were permitted.

The transform function used must be one of the following, as defined in the Sprite class:
Sprite.TRANS_NONE - causes the specified image region to be copied unchanged
Sprite.TRANS_ROT90 - causes the specified image region to be rotated clockwise by 90 degrees.
Sprite.TRANS_ROT180 - causes the specified image region to be rotated clockwise by 180 degrees.
Sprite.TRANS_ROT270 - causes the specified image region to be rotated clockwise by 270 degrees.
Sprite.TRANS_MIRROR - causes the specified image region to be reflected about its vertical center.
Sprite.TRANS_MIRROR_ROT90 - causes the specified image region to be reflected about its vertical center and then rotated clockwise by 90 degrees.
Sprite.TRANS_MIRROR_ROT180 - causes the specified image region to be reflected about its vertical center and then rotated clockwise by 180 degrees.
Sprite.TRANS_MIRROR_ROT270 - causes the specified image region to be reflected about its vertical center and then rotated clockwise by 270 degrees.

If the source region contains transparent pixels, the corresponding pixels in the destination region must be left untouched. If the source region contains partially transparent pixels, a compositing operation must be performed with the destination pixels, leaving all pixels of the destination region fully opaque.

The (x_src, y_src) coordinates are relative to the upper left corner of the source image. The x_src, y_src, width, and height parameters specify a rectangular region of the source image. It is illegal for this region to extend beyond the bounds of the source image. This requires that:

 x_src >= 0
 y_src >= 0
 x_src + width <= source width
 y_src + height <= source height    

The (x_dest, y_dest) coordinates are relative to the coordinate system of this Graphics object. It is legal for the destination area to extend beyond the bounds of the Graphics object. Pixels outside of the bounds of the Graphics object will not be drawn.

The transform is applied to the image data from the region of the source image, and the result is rendered with its anchor point positioned at location (x_dest, y_dest) in the destination.

Parameters:

src - - the source image to copy from

x_src - - the x coordinate of the upper left corner of the region within the source image to copy

y_src - - the y coordinate of the upper left corner of the region within the source image to copy

width - - the width of the region to copy

height - - the height of the region to copy

transform - - the desired transformation for the selected region being copied

x_dest - - the x coordinate of the anchor point in the destination drawing area

y_dest - - the y coordinate of the anchor point in the destination drawing area

anchor - - the anchor point for positioning the region within the destination image

Throws:

IllegalArgumentException - - if src is the same image as the destination of this Graphics object

NullPointerException - - if src is null

IllegalArgumentException - - if transform is invalid

IllegalArgumentException - - if anchor is invalid

IllegalArgumentException - - if the region to be copied exceeds the bounds of the source image

Since:

MIDP 2.0

drawRoundRect

void drawRoundRect(int x,
                   int y,
                   int width,
                   int height,
                   int arcWidth,
                   int arcHeight)

Draws the outline of the specified rounded corner rectangle using the current color and stroke style. The resulting rectangle will cover an area (width + 1) pixels wide by (height + 1) pixels tall. If either width or height is less than zero, nothing is drawn.

Parameters:

x - - the x coordinate of the rectangle to be drawn

y - - the y coordinate of the rectangle to be drawn

width - - the width of the rectangle to be drawn

height - - the height of the rectangle to be drawn

arcWidth - - the horizontal diameter of the arc at the four corners

arcHeight - - the vertical diameter of the arc at the four corners

See Also:

fillRoundRect(int, int, int, int, int, int)

fillRoundRect

void fillRoundRect(int x,
                   int y,
                   int width,
                   int height,
                   int arcWidth,
                   int arcHeight)

Fills the specified rounded corner rectangle with the current color. If either width or height is zero or less, nothing is drawn.

Parameters:

x - - the x coordinate of the rectangle to be filled

y - - the y coordinate of the rectangle to be filled

width - - the width of the rectangle to be filled

height - - the height of the rectangle to be filled

arcWidth - - the horizontal diameter of the arc at the four corners

arcHeight - - the vertical diameter of the arc at the four corners

See Also:

drawRoundRect(int, int, int, int, int, int)

fillArc

void fillArc(int x,
             int y,
             int width,
             int height,
             int startAngle,
             int arcAngle)

Fills a circular or elliptical arc covering the specified rectangle.

The resulting arc begins at startAngle and extends for arcAngle degrees. Angles are interpreted such that 0 degrees is at the 3 o'clock position. A positive value indicates a counter-clockwise rotation while a negative value indicates a clockwise rotation.

The center of the arc is the center of the rectangle whose origin is (x, y) and whose size is specified by the width and height arguments.

If either width or height is zero or less, nothing is drawn.

The filled region consists of the "pie wedge" region bounded by the arc segment as if drawn by drawArc(), the radius extending from the center to this arc at startAngle degrees, and radius extending from the center to this arc at startAngle + arcAngle degrees.

The angles are specified relative to the non-square extents of the bounding rectangle such that 45 degrees always falls on the line from the center of the ellipse to the upper right corner of the bounding rectangle. As a result, if the bounding rectangle is noticeably longer in one axis than the other, the angles to the start and end of the arc segment will be skewed farther along the longer axis of the bounds.

Parameters:

x - - the x coordinate of the upper-left corner of the arc to be filled.

y - - the y coordinate of the upper-left corner of the arc to be filled.

width - - the width of the arc to be filled

height - - the height of the arc to be filled

startAngle - - the beginning angle.

arcAngle - - the angular extent of the arc, relative to the start angle.

See Also:

drawArc(int, int, int, int, int, int)

drawArc

void drawArc(int x,
             int y,
             int width,
             int height,
             int startAngle,
             int arcAngle)

Draws the outline of a circular or elliptical arc covering the specified rectangle, using the current color and stroke style.

The resulting arc begins at startAngle and extends for arcAngle degrees, using the current color. Angles are interpreted such that 0 degrees is at the 3 o'clock position. A positive value indicates a counter-clockwise rotation while a negative value indicates a clockwise rotation.

The center of the arc is the center of the rectangle whose origin is (x, y) and whose size is specified by the width and height arguments.

The resulting arc covers an area width + 1 pixels wide by height + 1 pixels tall. If either width or height is less than zero, nothing is drawn.

The angles are specified relative to the non-square extents of the bounding rectangle such that 45 degrees always falls on the line from the center of the ellipse to the upper right corner of the bounding rectangle. As a result, if the bounding rectangle is noticeably longer in one axis than the other, the angles to the start and end of the arc segment will be skewed farther along the longer axis of the bounds.

Parameters:

x - - the x coordinate of the upper-left corner of the arc to be drawn

y - - the y coordinate of the upper-left corner of the arc to be drawn

width - - the width of the arc to be drawn

height - - the height of the arc to be drawn

startAngle - - the beginning angle

arcAngle - - the angular extent of the arc, relative to the start angle

See Also:

fillArc(int, int, int, int, int, int)

drawString

void drawString(String str,
                int x,
                int y,
                int anchor)

Draws the specified String using the current font and color. The x,y position is the position of the anchor point. See anchor points.

Parameters:

str - - the String to be drawn

x - - the x coordinate of the anchor point

y - - the y coordinate of the anchor point

anchor - - the anchor point for positioning the text

Throws:

NullPointerException - - if str is null

IllegalArgumentException - - if anchor is not a legal value

See Also:

drawChars(char[], int, int, int, int, int)

drawSubstring

void drawSubstring(String str,
                   int offset,
                   int len,
                   int x,
                   int y,
                   int anchor)

Draws the specified String using the current font and color. The x,y position is the position of the anchor point. See anchor points.

The offset and len parameters must specify a valid range of characters within the string str. The offset parameter must be within the range [0..(str.length())], inclusive. The len parameter must be a non-negative integer such that (offset + len) <= str.length().

Parameters:

str - - the String to be drawn

offset - - zero-based index of first character in the substring

len - - length of the substring

x - - the x coordinate of the anchor point

y - - the y coordinate of the anchor point

anchor - - the anchor point for positioning the text

Throws:

StringIndexOutOfBoundsException - - if offset and length do not specify a valid range within the String str

IllegalArgumentException - - if anchor is not a legal value

NullPointerException - - if str is null

See Also:

drawString(String, int, int, int).

drawChar

void drawChar(char character,
              int x,
              int y,
              int anchor)

Draws the specified character using the current font and color.

Parameters:

character - - the character to be drawn

x - - the x coordinate of the anchor point

y - - the y coordinate of the anchor point

anchor - - the anchor point for positioning the text; see anchor points

Throws:

IllegalArgumentException - - if anchor is not a legal value

See Also:

drawString(java.lang.String, int, int, int), drawChars(char[], int, int, int, int, int)

drawChars

void drawChars(char[] data,
               int offset,
               int length,
               int x,
               int y,
               int anchor)

Draws the specified characters using the current font and color.

The offset and length parameters must specify a valid range of characters within the character array data. The offset parameter must be within the range [0..(data.length)], inclusive. The length parameter must be a non-negative integer such that (offset + length) <= data.length.

Parameters:

data - - the array of characters to be drawn

offset - - the start offset in the data

length - - the number of characters to be drawn

x - - the x coordinate of the anchor point

y - - the y coordinate of the anchor point

anchor - - the anchor point for positioning the text; see anchor points

Throws:

ArrayIndexOutOfBoundsException - - if offset and length do not specify a valid range within the data array

IllegalArgumentException - - if anchor is not a legal value

NullPointerException - - if data is null

See Also:

drawString(java.lang.String, int, int, int)

drawImage

void drawImage(Image img,
               int x,
               int y,
               int anchor)

Draws the specified image by using the anchor point. The image can be drawn in different positions relative to the anchor point by passing the appropriate position constants. See anchor points.

If the source image contains transparent pixels, the corresponding pixels in the destination image must be left untouched. If the source image contains partially transparent pixels, a compositing operation must be performed with the destination pixels, leaving all pixels of the destination image fully opaque.

If img is the same as the destination of this Graphics object, the result is undefined. For copying areas within an Image, copyArea should be used instead.

Parameters:

img - - the specified image to be drawn

x - - the x coordinate of the anchor point

y - - the y coordinate of the anchor point

anchor - - the anchor point for positioning the image

Throws:

IllegalArgumentException - - if anchor is not a legal value

NullPointerException - - if img is null

See Also:

Image

copyArea

void copyArea(int x_src,
              int y_src,
              int width,
              int height,
              int x_dest,
              int y_dest,
              int anchor)

Copies the contents of a rectangular area (x_src, y_src, width, height) to a destination area, whose anchor point identified by anchor is located at (x_dest, y_dest). The effect must be that the destination area contains an exact copy of the contents of the source area immediately prior to the invocation of this method. This result must occur even if the source and destination areas overlap.

The points (x_src, y_src) and (x_dest, y_dest) are both specified relative to the coordinate system of the Graphics object. It is illegal for the source region to extend beyond the bounds of the graphic object. This requires that:

 x_src + tx >= 0
 y_src + ty >= 0
 x_src + tx + width <= width of Graphics object's destination
 y_src + ty + height <= height of Graphics object's destination      

where tx and ty represent the X and Y coordinates of the translated origin of this graphics object, as returned by getTranslateX() and getTranslateY(), respectively.

However, it is legal for the destination area to extend beyond the bounds of the Graphics object. Pixels outside of the bounds of the Graphics object will not be drawn.

The copyArea method is allowed on all Graphics objects except those whose destination is the actual display device. This restriction is necessary because allowing a copyArea method on the display would adversely impact certain techniques for implementing double-buffering.

Like other graphics operations, the copyArea method uses the Source Over Destination rule for combining pixels. However, since it is defined only for mutable images, which can contain only fully opaque pixels, this is effectively the same as pixel replacement.

Parameters:

x_src - - the x coordinate of upper left corner of source area

y_src - - the y coordinate of upper left corner of source area

width - - the width of the source area

height - - the height of the source area

x_dest - - the x coordinate of the destination anchor point

y_dest - - the y coordinate of the destination anchor point

anchor - - the anchor point for positioning the region within the destination image

Throws:

IllegalStateException - - if the destination of this Graphics object is the display device

IllegalArgumentException - - if the region to be copied exceeds the bounds of the source image

Since:

MIDP 2.0

fillTriangle

void fillTriangle(int x1,
                  int y1,
                  int x2,
                  int y2,
                  int x3,
                  int y3)

Fills the specified triangle will the current color. The lines connecting each pair of points are included in the filled triangle.

Parameters:

x1 - - the x coordinate of the first vertex of the triangle

y1 - - the y coordinate of the first vertex of the triangle

x2 - - the x coordinate of the second vertex of the triangle

y2 - - the y coordinate of the second vertex of the triangle

x3 - - the x coordinate of the third vertex of the triangle

y3 - - the y coordinate of the third vertex of the triangle

Since:

MIDP 2.0

drawRGB

void drawRGB(int[] rgbData,
             int offset,
             int scanlength,
             int x,
             int y,
             int width,
             int height,
             boolean processAlpha)

Renders a series of device-independent RGB+transparency values in a specified region. The values are stored in rgbData in a format with 24 bits of RGB and an eight-bit alpha value (0xAARRGGBB), with the first value stored at the specified offset. The scanlength specifies the relative offset within the array between the corresponding pixels of consecutive rows. Any value for scanlength is acceptable (even negative values) provided that all resulting references are within the bounds of the rgbData array. The ARGB data is rasterized horizontally from left to right within each row. The ARGB values are rendered in the region specified by x, y, width and height, and the operation is subject to the current clip region and translation for this Graphics object.

Consider P(a,b) to be the value of the pixel located at column a and row b of the Image, where rows and columns are numbered downward from the top starting at zero, and columns are numbered rightward from the left starting at zero. This operation can then be defined as:

 P(a, b) = rgbData[offset + (a - x) + (b - y) * scanlength]       

for

 x <= a < x + width
 y <= b < y + height    

This capability is provided in the Graphics class so that it can be used to render both to the screen and to offscreen Image objects. The ability to retrieve ARGB values is provided by the Image.getRGB(int[], int, int, int, int, int, int) method.

If processAlpha is true, the high-order byte of the ARGB format specifies opacity; that is, 0x00RRGGBB specifies a fully transparent pixel and 0xFFRRGGBB specifies a fully opaque pixel. Intermediate alpha values specify semitransparency. If the implementation does not support alpha blending for image rendering operations, it must remove any semitransparency from the source data prior to performing any rendering. (See Alpha Processing for further discussion.) If processAlpha is false, the alpha values are ignored and all pixels must be treated as completely opaque.

The mapping from ARGB values to the device-dependent pixels is platform-specific and may require significant computation.

Parameters:

rgbData - - an array of ARGB values in the format 0xAARRGGBB

offset - - the array index of the first ARGB value

scanlength - - the relative array offset between the corresponding pixels in consecutive rows in the rgbData array

x - - the horizontal location of the region to be rendered

y - - the vertical location of the region to be rendered

width - - the width of the region to be rendered

height - - the height of the region to be rendered

processAlpha - - true if rgbData has an alpha channel, false if all pixels are fully opaque

Throws:

ArrayIndexOutOfBoundsException - - if the requested operation will attempt to access an element of rgbData whose index is either negative or beyond its length

NullPointerException - - if rgbData is null

Since:

MIDP 2.0

getDisplayColor

int getDisplayColor(int color)

Gets the color that will be displayed if the specified color is requested. This method enables the developer to check the manner in which RGB values are mapped to the set of distinct colors that the device can actually display. For example, with a monochrome device, this method will return either 0xFFFFFF (white) or 0x000000 (black) depending on the brightness of the specified color.

Parameters:

color - - the desired color (in 0x00RRGGBB format, the high-order byte is ignored)

Returns:

the corresponding color that will be displayed on the device's screen (in 0x00RRGGBB format)

Since:

MIDP 2.0