org.razvan.jzx
Class BaseScreen

java.lang.Object
  java.awt.Component
      java.awt.Canvas
          org.razvan.jzx.BaseScreen

All Implemented Interfaces:

java.awt.image.ImageObserver, java.awt.MenuContainer, java.io.Serializable, javax.accessibility.Accessible

Direct Known Subclasses:

ScreenBoth, ScreenJava1, ScreenJava2

public abstract class BaseScreen
extends java.awt.Canvas

Base class extended by all screen components that comprise the emulator.

Note: BaseScreen must extend Canvas, so it does not extend BaseComponent, although it (correctly) should. Instead, it implements all the BaseComponent methods explicitly.

This class provides basic, common screen functionality for the screen subsystem of the emulator. Specific methods are overriden or implemented so as to comply with the idiosyncracies of various JVM versions. There are no differences between the Spectrum 48k and the Spectrum 128k models.

Author:

Razvan Surdulescu (c) 2001 - 2006, Erik Kunze (c) 1995, 1996, 1997, Des Herriott (c) 1993, 1994
You may use and distribute this software for free provided you include this copyright notice. You may not sell this software, use my name for publicity reasons or modify the code without permission from me.

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class java.awt.Canvas

java.awt.Canvas.AccessibleAWTCanvas

Nested classes/interfaces inherited from class java.awt.Component

java.awt.Component.AccessibleAWTComponent, java.awt.Component.BltBufferStrategy, java.awt.Component.FlipBufferStrategy

Field Summary

static int	ATTR_LENGTH Length of attribute memory area.
static int	ATTR_START Memory address where the attribute area starts.
static int	BLACK The Spectrum index of the color "black"
static int	BLUE The Spectrum index of the color "blue"
static int	BORDER_PIXELS Width of border area, in pixels.
static int	BRIGHT Bright attribute mask.
static int	BRIGHT_BLACK The Spectrum index of the color "bright black"
static int	BRIGHT_BLUE The Spectrum index of the color "bright blue"
static int	BRIGHT_CYAN The Spectrum index of the color "bright cyan"
static int	BRIGHT_GREEN The Spectrum index of the color "bright green"
static int	BRIGHT_MAGENTA The Spectrum index of the color "bright magenta"
static int	BRIGHT_RED The Spectrum index of the color "bright red"
static int	BRIGHT_WHITE The Spectrum index of the color "bright white"
static int	BRIGHT_YELLOW The Spectrum index of the color "bright yellow"
static int	COLS Number of character columns on the screen.
static int	CYAN The Spectrum index of the color "cyan"
static int	FLASH Flash attribute mask.
static int	GREEN The Spectrum index of the color "green"
static int	INK Ink attribute mask.
protected int	m_borderColor The current border color.
protected boolean	m_borderDirty If true, the border needs repainting.
protected boolean	m_flashPhase Is the flash phase normal or inverted?
protected int[]	m_inkTable Maps a given attribute value to its corresponding ink value, to avoid having to decode it explicitly.
protected ILogger	m_logger The ILogger object used to logStream information and exceptions.
protected java.awt.Image	m_offscreenBorder The image that renders the border and the screen.
protected java.awt.Graphics	m_offscreenBorderGraphics The Graphics object corresponding to the border image.
protected java.awt.Image	m_offscreenImage The image that renders the screen.
protected java.awt.Graphics	m_offscreenImageGraphics The Graphics object corresponding to the screen image.
protected int[]	m_paperTable Maps a given attribute value to its corresponding paper value, to avoid having to decode it explicitly.
protected int	m_scale The screen scaling factor.
protected boolean[]	m_screenChanged Bit vector that indicates whether a particular memory byte has been changed.
protected boolean	m_screenDirty If true, the screen needs repainting.
protected int	m_screenHeight The screen height, in pixels (uses m_scale.)
protected int	m_screenWidth The screen width, in pixels (uses m_scale.)
protected BaseSpectrum	m_spectrum Cached reference to the BaseSpectrum object.
static int	MAGENTA The Spectrum index of the color "magenta"
static int	PAPER Paper attribute mask.
static int	PIXEL_LENGTH Length of pixel memory area.
static int	PIXEL_START Memory address where the screen area starts.
static int	RED The Spectrum index of the color "red"
static int	ROWS Number of character rows on the screen.
protected static java.awt.Color[]	s_colorPalette An array of Color objects corresponding to the color indices above.
protected static int[]	s_rgbPalette An array of RGB integral values corresponding to the color indices above.
static int	WHITE The Spectrum index of the color "white"
static int	X_PIXELS Number of X pixels on the screen.
static int	Y_PIXELS Number of Y pixels on the screen.
static int	YELLOW The Spectrum index of the color "yellow"

Fields inherited from class java.awt.Component

BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT

Fields inherited from interface java.awt.image.ImageObserver

ABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH

Constructor Summary

BaseScreen()

Method Summary

void	attrTouch(int addr16) Touch a particular attribute value, marking it for update next time the screen is rendered.
void	clear(int attr) Clear the screen with the given attribute color.
void	clear(int width, int height, int attr) Clear a box on the screen, with upper-left corner at the current cursor position, with given height and width using the given attribute color.
protected java.awt.Image	createCompatibleImage(int width, int height) Create and return an Image object that isa appropriate for this Screen object.
protected abstract void	draw8(int x, int y, int pix8, int attr8) Draws the given 8 bits (pix8), with the given attribute values (attr8) at coordinates x, y on the Canvas.
void	dumpScreenshot()
protected void	endRender() Trigger method that is called right afterthe screen is rendered.
void	flash() When the flash phase changes, update all attribute values that have the flash bit set.
int	getCursorX() Retrieve current cursor X position.
int	getCursorY() Retrieve current cursor Y position.
static BaseScreen	getInstance() Construct the appropriate (derived class) instance for the current environment (JVM version.)
java.awt.Dimension	getMinimumSize() Set the minimum size to (full width, full height).
int	getPage() Trivial accessor to the physical memory page for the screen data.
java.awt.Dimension	getPreferredSize() Set the preferred size to (full width, full height).
void	init(BaseSpectrum spectrum, ILogger logger) Set cached pointers to the BaseSpectrum and BaseMemory objects. Allocate pixel modification bit vector. Allocate ink and paper tables. Set the size of the Canvas object, and add it to the Container. Add the keyboard object as the KeyListener. Set the scale.
void	load(BaseLoader loader) Load the screen contents from the given BaseLoader object.
void	paint(java.awt.Graphics g) If the screen is dirty, update it by walking the memory page and re-drawing the data that has changed.
void	print(char letter, int attr) Print a given character at the current cursor position and advance the cursor X position by 1.
void	print(java.lang.String string, int attr) Call print(char, int) for every character in the given string.
void	println(char letter, int attr) Call print(char, int) and advance the cursor Y position by 1.
void	println(java.lang.String string, int attr) Call print(String, int) with the given string, then set the cursor to be on the line immediately underneath the original cursor position.
void	reset() Touch all the screen bits in order to force the initial refresh.
void	screenTouch(int addr16) Touch a particular byte value in screen memory, marking it for update next time the screen is rendered.
void	setBorderColor(int val8) Change the current border color, and mark the border as dirty for update at the next screen refresh.
void	setCursor(int x, int y) Set the current cursor position used by print methods below.
void	setPage(int page) Trivial mutator for the physical memory page for the screen data.
protected void	setScale(int scale) Non-trivial mutator for the screen scale value.
protected void	startRender() Trigger method that is called right before the screen is rendered.
void	terminate() Release all cached pointers, set all the tables to null.
void	update(java.awt.Graphics g) Redraw the screen, but do not erase it first in order to avoid flicker.

Methods inherited from class java.awt.Canvas

addNotify, createBufferStrategy, createBufferStrategy, getAccessibleContext, getBufferStrategy

Methods inherited from class java.awt.Component

action, add, addComponentListener, addFocusListener, addHierarchyBoundsListener, addHierarchyListener, addInputMethodListener, addKeyListener, addMouseListener, addMouseMotionListener, addMouseWheelListener, addPropertyChangeListener, addPropertyChangeListener, applyComponentOrientation, areFocusTraversalKeysSet, bounds, checkImage, checkImage, coalesceEvents, contains, contains, createImage, createImage, createVolatileImage, createVolatileImage, deliverEvent, disable, disableEvents, dispatchEvent, doLayout, enable, enable, enableEvents, enableInputMethods, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, getAlignmentX, getAlignmentY, getBackground, getBounds, getBounds, getColorModel, getComponentAt, getComponentAt, getComponentListeners, getComponentOrientation, getCursor, getDropTarget, getFocusCycleRootAncestor, getFocusListeners, getFocusTraversalKeys, getFocusTraversalKeysEnabled, getFont, getFontMetrics, getForeground, getGraphics, getGraphicsConfiguration, getHeight, getHierarchyBoundsListeners, getHierarchyListeners, getIgnoreRepaint, getInputContext, getInputMethodListeners, getInputMethodRequests, getKeyListeners, getListeners, getLocale, getLocation, getLocation, getLocationOnScreen, getMaximumSize, getMouseListeners, getMouseMotionListeners, getMousePosition, getMouseWheelListeners, getName, getParent, getPeer, getPropertyChangeListeners, getPropertyChangeListeners, getSize, getSize, getToolkit, getTreeLock, getWidth, getX, getY, gotFocus, handleEvent, hasFocus, hide, imageUpdate, inside, invalidate, isBackgroundSet, isCursorSet, isDisplayable, isDoubleBuffered, isEnabled, isFocusable, isFocusCycleRoot, isFocusOwner, isFocusTraversable, isFontSet, isForegroundSet, isLightweight, isMaximumSizeSet, isMinimumSizeSet, isOpaque, isPreferredSizeSet, isShowing, isValid, isVisible, keyDown, keyUp, layout, list, list, list, list, list, locate, location, lostFocus, minimumSize, mouseDown, mouseDrag, mouseEnter, mouseExit, mouseMove, mouseUp, move, nextFocus, paintAll, paramString, postEvent, preferredSize, prepareImage, prepareImage, print, printAll, processComponentEvent, processEvent, processFocusEvent, processHierarchyBoundsEvent, processHierarchyEvent, processInputMethodEvent, processKeyEvent, processMouseEvent, processMouseMotionEvent, processMouseWheelEvent, remove, removeComponentListener, removeFocusListener, removeHierarchyBoundsListener, removeHierarchyListener, removeInputMethodListener, removeKeyListener, removeMouseListener, removeMouseMotionListener, removeMouseWheelListener, removeNotify, removePropertyChangeListener, removePropertyChangeListener, repaint, repaint, repaint, repaint, requestFocus, requestFocus, requestFocusInWindow, requestFocusInWindow, reshape, resize, resize, setBackground, setBounds, setBounds, setComponentOrientation, setCursor, setDropTarget, setEnabled, setFocusable, setFocusTraversalKeys, setFocusTraversalKeysEnabled, setFont, setForeground, setIgnoreRepaint, setLocale, setLocation, setLocation, setMaximumSize, setMinimumSize, setName, setPreferredSize, setSize, setSize, setVisible, show, show, size, toString, transferFocus, transferFocusBackward, transferFocusUpCycle, validate

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

PIXEL_START

public static final int PIXEL_START

Memory address where the screen area starts.

See Also:

Constant Field Values

ROWS

public static final int ROWS

Number of character rows on the screen.

See Also:

Constant Field Values

COLS

public static final int COLS

Number of character columns on the screen.

See Also:

Constant Field Values

X_PIXELS

public static final int X_PIXELS

Number of X pixels on the screen.

See Also:

Constant Field Values

Y_PIXELS

public static final int Y_PIXELS

Number of Y pixels on the screen.

See Also:

Constant Field Values

PIXEL_LENGTH

public static final int PIXEL_LENGTH

Length of pixel memory area.

See Also:

Constant Field Values

ATTR_START

public static final int ATTR_START

Memory address where the attribute area starts.

See Also:

Constant Field Values

ATTR_LENGTH

public static final int ATTR_LENGTH

Length of attribute memory area.

See Also:

Constant Field Values

BORDER_PIXELS

public static final int BORDER_PIXELS

Width of border area, in pixels.

See Also:

Constant Field Values

BLACK

public static final int BLACK

The Spectrum index of the color "black"

See Also:

Constant Field Values

BLUE

public static final int BLUE

The Spectrum index of the color "blue"

See Also:

Constant Field Values

RED

public static final int RED

The Spectrum index of the color "red"

See Also:

Constant Field Values

MAGENTA

public static final int MAGENTA

The Spectrum index of the color "magenta"

See Also:

Constant Field Values

GREEN

public static final int GREEN

The Spectrum index of the color "green"

See Also:

Constant Field Values

CYAN

public static final int CYAN

The Spectrum index of the color "cyan"

See Also:

Constant Field Values

YELLOW

public static final int YELLOW

The Spectrum index of the color "yellow"

See Also:

Constant Field Values

WHITE

public static final int WHITE

The Spectrum index of the color "white"

See Also:

Constant Field Values

BRIGHT_BLACK

public static final int BRIGHT_BLACK

The Spectrum index of the color "bright black"

See Also:

Constant Field Values

BRIGHT_BLUE

public static final int BRIGHT_BLUE

The Spectrum index of the color "bright blue"

See Also:

Constant Field Values

BRIGHT_RED

public static final int BRIGHT_RED

The Spectrum index of the color "bright red"

See Also:

Constant Field Values

BRIGHT_MAGENTA

public static final int BRIGHT_MAGENTA

The Spectrum index of the color "bright magenta"

See Also:

Constant Field Values

BRIGHT_GREEN

public static final int BRIGHT_GREEN

The Spectrum index of the color "bright green"

See Also:

Constant Field Values

BRIGHT_CYAN

public static final int BRIGHT_CYAN

The Spectrum index of the color "bright cyan"

See Also:

Constant Field Values

BRIGHT_YELLOW

public static final int BRIGHT_YELLOW

The Spectrum index of the color "bright yellow"

See Also:

Constant Field Values

BRIGHT_WHITE

public static final int BRIGHT_WHITE

The Spectrum index of the color "bright white"

See Also:

Constant Field Values

FLASH

public static final int FLASH

Flash attribute mask.

See Also:

Constant Field Values

BRIGHT

public static final int BRIGHT

Bright attribute mask.

See Also:

Constant Field Values

PAPER

public static final int PAPER

Paper attribute mask.

See Also:

Constant Field Values

INK

public static final int INK

Ink attribute mask.

See Also:

Constant Field Values

m_scale

protected int m_scale

The screen scaling factor.

m_screenWidth

protected int m_screenWidth

The screen width, in pixels (uses m_scale.)

m_screenHeight

protected int m_screenHeight

The screen height, in pixels (uses m_scale.)

s_colorPalette

protected static final java.awt.Color[] s_colorPalette

An array of Color objects corresponding to the color indices above.

s_rgbPalette

protected static final int[] s_rgbPalette

An array of RGB integral values corresponding to the color indices above.

m_flashPhase

protected boolean m_flashPhase

Is the flash phase normal or inverted?

m_borderColor

protected int m_borderColor

The current border color.

m_inkTable

protected int[] m_inkTable

Maps a given attribute value to its corresponding ink value, to avoid having to decode it explicitly.

m_paperTable

protected int[] m_paperTable

Maps a given attribute value to its corresponding paper value, to avoid having to decode it explicitly.

m_screenChanged

protected boolean[] m_screenChanged

Bit vector that indicates whether a particular memory byte has been changed.

m_screenDirty

protected boolean m_screenDirty

If true, the screen needs repainting.

m_borderDirty

protected boolean m_borderDirty

If true, the border needs repainting.

m_offscreenBorder

protected java.awt.Image m_offscreenBorder

The image that renders the border and the screen.

m_offscreenBorderGraphics

protected java.awt.Graphics m_offscreenBorderGraphics

The Graphics object corresponding to the border image.

m_offscreenImage

protected java.awt.Image m_offscreenImage

The image that renders the screen.

m_offscreenImageGraphics

protected java.awt.Graphics m_offscreenImageGraphics

The Graphics object corresponding to the screen image.

m_spectrum

protected BaseSpectrum m_spectrum

Cached reference to the BaseSpectrum object.

m_logger

protected ILogger m_logger

The ILogger object used to logStream information and exceptions.

Constructor Detail

BaseScreen

public BaseScreen()

Method Detail

init

public void init(BaseSpectrum spectrum,
                 ILogger logger)

• Set cached pointers to the BaseSpectrum and BaseMemory objects.
• Allocate pixel modification bit vector.
• Allocate ink and paper tables.
• Set the size of the Canvas object, and add it to the Container.
• Add the keyboard object as the KeyListener.
• Set the scale.

reset

public void reset()

Touch all the screen bits in order to force the initial refresh.

terminate

public void terminate()

Release all cached pointers, set all the tables to null.

getPage

public int getPage()

Trivial accessor to the physical memory page for the screen data.

setPage

public void setPage(int page)

Trivial mutator for the physical memory page for the screen data.

setScale

protected void setScale(int scale)

Non-trivial mutator for the screen scale value.

This method updates all the screen size parameters in accordance to the new scale value. This method should be appropriately overriden by child classes in order to to modify their inner structures if the scale is changed.

getMinimumSize

public java.awt.Dimension getMinimumSize()

Set the minimum size to (full width, full height).

Overrides:

getMinimumSize in class java.awt.Component

getPreferredSize

public java.awt.Dimension getPreferredSize()

Set the preferred size to (full width, full height).

Overrides:

getPreferredSize in class java.awt.Component

update

public void update(java.awt.Graphics g)

Redraw the screen, but do not erase it first in order to avoid flicker. This method just calls paint(java.awt.Graphics) with the specified Graphics context.

Overrides:

update in class java.awt.Canvas

paint

public void paint(java.awt.Graphics g)

If the screen is dirty, update it by walking the memory page and re-drawing the data that has changed.

Call the abstract draw8() method below to do the actual work for every pixel.

Note that there exists a benign race condition in this code: a PAINT event may be issued as the CPU is decoding instructions and updating the screen from the main thread. The reason this race condition is benign is because in the worst case it can cause aliasing: the screen contents are changed half way through a frame. Fixing this race condition would involve making a copy of the screen memory page, which hurts performance.

Overrides:

paint in class java.awt.Canvas

See Also:

draw8(int, int, int, int)

createCompatibleImage

protected java.awt.Image createCompatibleImage(int width,
                                               int height)

Create and return an Image object that isa appropriate for this Screen object.

Override this method to return image types that are optimized for the particular JVM and/or platform.

startRender

protected void startRender()

Trigger method that is called right before the screen is rendered.

Override this method to receive a notification.

endRender

protected void endRender()

Trigger method that is called right afterthe screen is rendered.

Override this method to receive a notification.

draw8

protected abstract void draw8(int x,
                              int y,
                              int pix8,
                              int attr8)

Draws the given 8 bits (pix8), with the given attribute values (attr8) at coordinates x, y on the Canvas.

This method is implemented as appropriate for performance reasons in the various child classes.

Parameters:

x - The X coordinate where the pixels should be drawn onto the Canvas object.

y - The Y coordinat where the pixels should be drawn onto the Canvas object.

pix8 - The 8 bits to draw starting at (X,Y) ending at (X+8,Y).

attr8 - The attributes used to draw the 8 bits.

flash

public void flash()

When the flash phase changes, update all attribute values that have the flash bit set.

The next time the screen is rendered, all flash attributes will appear correctly.

attrTouch

public void attrTouch(int addr16)

Touch a particular attribute value, marking it for update next time the screen is rendered.

The touching of an attribute entails touching the 8 byte values whose screen representation is altered by this attribute value.

Parameters:

addr16 - The 16-bit absolute memory address (in the attribute memory area) which should be touched.

screenTouch

public void screenTouch(int addr16)

Touch a particular byte value in screen memory, marking it for update next time the screen is rendered.

Parameters:

addr16 - The 16-bit absolute memory address (in the screen memory area) which should be touched.

setBorderColor

public void setBorderColor(int val8)

Change the current border color, and mark the border as dirty for update at the next screen refresh.

setCursor

public void setCursor(int x,
                      int y)

Set the current cursor position used by print methods below.

Parameters:

x - New cursor X position

y - New cursor Y position

See Also:

print(char, int), println(char, int), print(String, int), println(String, int)

getCursorX

public int getCursorX()

Retrieve current cursor X position.

Returns:

Current cursor X position

getCursorY

public int getCursorY()

Retrieve current cursor Y position.

Returns:

Current cursor Y position

clear

public void clear(int attr)

Clear the screen with the given attribute color.

Parameters:

attr - Attribute color used to clear the screen

clear

public void clear(int width,
                  int height,
                  int attr)

Clear a box on the screen, with upper-left corner at the current cursor position, with given height and width using the given attribute color.

Parameters:

width - Width of box to clear

height - Height of box to clear

attr - Attribute color used to clear

print

public void print(char letter,
                  int attr)

Print a given character at the current cursor position and advance the cursor X position by 1. If the cursor falls outside the bounds of the screen, do not display anything. If the letter is invalid (not in the interval [32, 127]) display '?'. You must manually call Component.repaint()

Parameters:

letter - The letter to print on the screen

attr - The attribute used to print the letter on the screen

println

public void println(char letter,
                    int attr)

Call print(char, int) and advance the cursor Y position by 1.

Parameters:

letter - The letter to print on the screen

attr - The attribute used to print the letter on the screen

See Also:

print(char, int)

print

public void print(java.lang.String string,
                  int attr)

Call print(char, int) for every character in the given string.

Parameters:

string - The string to print on the screen

attr - The attribute used to print the letter on the screen

See Also:

print(char, int)

println

public void println(java.lang.String string,
                    int attr)

Call print(String, int) with the given string, then set the cursor to be on the line immediately underneath the original cursor position.

Parameters:

string - The string to print on the screen

attr - The attribute used to print the letter on the screen

See Also:

print(String, int)

load

public void load(BaseLoader loader)

Load the screen contents from the given BaseLoader object.

Since the screen data is not saved, this method does nothing.

getInstance

public static BaseScreen getInstance()

Construct the appropriate (derived class) instance for the current environment (JVM version.)

The method constructs an instance of ScreenJava1 if the JVM is version 1.1.x, and an instance of ScreenJava2 if the JVM is version of 1.2.x.

See Also:

ScreenJava1, ScreenJava2, ScreenBoth

dumpScreenshot

public void dumpScreenshot()