Android Open Source - ZShaolin Transcript Screen

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The source code is released under:

GNU General Public License

Java Source Code

/*
 * Copyright (C) 2007 The Android Open Source Project
 */* www.ja  v  a  2s  . c  o m*/
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.spartacusrex.spartacuside.session;

import android.graphics.Canvas;
import android.util.Log;

import com.spartacusrex.spartacuside.model.Screen;
import com.spartacusrex.spartacuside.model.TextRenderer;

/**
 * A TranscriptScreen is a screen that remembers data that's been scrolled. The
 * old data is stored in a ring buffer to minimize the amount of copying that
 * needs to be done. The transcript does its own drawing, to avoid having to
 * expose its internal data structures.
 */
public class TranscriptScreen implements Screen {
    private static final String TAG = "TranscriptScreen";

    /**
     * The width of the transcript, in characters. Fixed at initialization.
     */
    private int mColumns;

    /**
     * The total number of rows in the transcript and the screen. Fixed at
     * initialization.
     */
    private int mTotalRows;

    /**
     * The number of rows in the active portion of the transcript. Doesn't
     * include the screen.
     */
    private int mActiveTranscriptRows;

    /**
     * Which row is currently the topmost line of the transcript. Used to
     * implement a circular buffer.
     */
    private int mHead;

    /**
     * The number of active rows, includes both the transcript and the screen.
     */
    private int mActiveRows;

    /**
     * The number of rows in the screen.
     */
    private int mScreenRows;

    /**
     * The data for both the screen and the transcript. The first mScreenRows *
     * mLineWidth characters are the screen, the rest are the transcript.
     * The low byte encodes the ASCII character, the high byte encodes the
     * foreground and background colors, plus underline and bold.
     */
    private char[] mData;

    /**
     * The data's stored as color-encoded chars, but the drawing routines require chars, so we
     * need a temporary buffer to hold a row's worth of characters.
     */
    private char[] mRowBuffer;

    /**
     * Flags that keep track of whether the current line logically wraps to the
     * next line. This is used when resizing the screen and when copying to the
     * clipboard or an email attachment
     */

    private boolean[] mLineWrap;

    /**
     * Create a transcript screen.
     *
     * @param columns the width of the screen in characters.
     * @param totalRows the height of the entire text area, in rows of text.
     * @param screenRows the height of just the screen, not including the
     *        transcript that holds lines that have scrolled off the top of the
     *        screen.
     */
    public TranscriptScreen(int columns, int totalRows, int screenRows,
            int foreColor, int backColor) {
        init(columns, totalRows, screenRows, foreColor, backColor);
    }

    private void init(int columns, int totalRows, int screenRows, int foreColor, int backColor) {
        mColumns = columns;
        mTotalRows = totalRows;
        mActiveTranscriptRows = 0;
        mHead = 0;
        mActiveRows = screenRows;
        mScreenRows = screenRows;
        int totalSize = columns * totalRows;
        mData = new char[totalSize];
        blockSet(0, 0, mColumns, mScreenRows, ' ', foreColor, backColor);
        mRowBuffer = new char[columns];
        mLineWrap = new boolean[totalRows];
        consistencyCheck();
   }

    public void finish() {
        /*
         * The Android InputMethodService will sometimes hold a reference to
         * us for a while after the activity closes, which is expensive because
         * it means holding on to the now-useless mData array.  Explicitly
         * get rid of our references to this data to help keep the amount of
         * memory being leaked down.
         */
        mData = null;
        mRowBuffer = null;
        mLineWrap = null;
    }

    /**
     * Convert a row value from the public external coordinate system to our
     * internal private coordinate system. External coordinate system:
     * -mActiveTranscriptRows to mScreenRows-1, with the screen being
     * 0..mScreenRows-1 Internal coordinate system: 0..mScreenRows-1 rows of
     * mData are the visible rows. mScreenRows..mActiveRows - 1 are the
     * transcript, stored as a circular buffer.
     *
     * @param row a row in the external coordinate system.
     * @return The row corresponding to the input argument in the private
     *         coordinate system.
     */
    private int externalToInternalRow(int row) {
        if (row < -mActiveTranscriptRows || row >= mScreenRows) {
            String errorMessage = "externalToInternalRow "+ row +
                " " + mActiveTranscriptRows + " " + mScreenRows;
            Log.e(TAG, errorMessage);
            throw new IllegalArgumentException(errorMessage);
        }
        if (row >= 0) {
            return row; // This is a visible row.
        }
        return mScreenRows
                + ((mHead + mActiveTranscriptRows + row) % mActiveTranscriptRows);
    }

    private int getOffset(int externalLine) {
        return externalToInternalRow(externalLine) * mColumns;
    }

    private int getOffset(int x, int y) {
        return getOffset(y) + x;
    }

    public void setLineWrap(int row) {
        mLineWrap[externalToInternalRow(row)] = true;
    }

    /**
     * Store byte b into the screen at location (x, y)
     *
     * @param x X coordinate (also known as column)
     * @param y Y coordinate (also known as row)
     * @param b ASCII character to store
     * @param foreColor the foreground color
     * @param backColor the background color
     */
    public void set(int x, int y, byte b, int foreColor, int backColor) {
        mData[getOffset(x, y)] = encode(b, foreColor, backColor);
    }

    private char encode(int b, int foreColor, int backColor) {
        return (char) ((foreColor << 12) | (backColor << 8) | b);
    }

    /**
     * Scroll the screen down one line. To scroll the whole screen of a 24 line
     * screen, the arguments would be (0, 24).
     *
     * @param topMargin First line that is scrolled.
     * @param bottomMargin One line after the last line that is scrolled.
     */
    public void scroll(int topMargin, int bottomMargin, int foreColor,
            int backColor) {
        // Separate out reasons so that stack crawls help us
        // figure out which condition was violated.
        if (topMargin > bottomMargin - 1) {
            throw new IllegalArgumentException();
        }

        if (topMargin > mScreenRows - 1) {
            throw new IllegalArgumentException();
        }

        if (bottomMargin > mScreenRows) {
            throw new IllegalArgumentException();
        }

        // Adjust the transcript so that the last line of the transcript
        // is ready to receive the newly scrolled data
        consistencyCheck();
        int expansionRows = Math.min(1, mTotalRows - mActiveRows);
        int rollRows = 1 - expansionRows;
        mActiveRows += expansionRows;
        mActiveTranscriptRows += expansionRows;
        if (mActiveTranscriptRows > 0) {
            mHead = (mHead + rollRows) % mActiveTranscriptRows;
        }
        consistencyCheck();

        // Block move the scroll line to the transcript
        int topOffset = getOffset(topMargin);
        int destOffset = getOffset(-1);
        System.arraycopy(mData, topOffset, mData, destOffset, mColumns);

        int topLine = externalToInternalRow(topMargin);
        int destLine = externalToInternalRow(-1);
        System.arraycopy(mLineWrap, topLine, mLineWrap, destLine, 1);

        // Block move the scrolled data up
        int numScrollChars = (bottomMargin - topMargin - 1) * mColumns;
        System.arraycopy(mData, topOffset + mColumns, mData, topOffset,
                numScrollChars);
        int numScrollLines = (bottomMargin - topMargin - 1);
        System.arraycopy(mLineWrap, topLine + 1, mLineWrap, topLine,
                numScrollLines);

        // Erase the bottom line of the scroll region
        blockSet(0, bottomMargin - 1, mColumns, 1, ' ', foreColor, backColor);
        mLineWrap[externalToInternalRow(bottomMargin-1)] = false;
    }

    private void consistencyCheck() {
        checkPositive(mColumns);
        checkPositive(mTotalRows);
        checkRange(0, mActiveTranscriptRows, mTotalRows);
        if (mActiveTranscriptRows == 0) {
            checkEqual(mHead, 0);
        } else {
            checkRange(0, mHead, mActiveTranscriptRows-1);
        }
        checkEqual(mScreenRows + mActiveTranscriptRows, mActiveRows);
        checkRange(0, mScreenRows, mTotalRows);

        checkEqual(mTotalRows, mLineWrap.length);
        checkEqual(mTotalRows*mColumns, mData.length);
        checkEqual(mColumns, mRowBuffer.length);
    }

    private void checkPositive(int n) {
        if (n < 0) {
            throw new IllegalArgumentException("checkPositive " + n);
        }
    }

    private void checkRange(int a, int b, int c) {
        if (a > b || b > c) {
            throw new IllegalArgumentException("checkRange " + a + " <= " + b + " <= " + c);
        }
    }

    private void checkEqual(int a, int b) {
        if (a != b) {
            throw new IllegalArgumentException("checkEqual " + a + " == " + b);
        }
    }

    /**
     * Block copy characters from one position in the screen to another. The two
     * positions can overlap. All characters of the source and destination must
     * be within the bounds of the screen, or else an InvalidParemeterException
     * will be thrown.
     *
     * @param sx source X coordinate
     * @param sy source Y coordinate
     * @param w width
     * @param h height
     * @param dx destination X coordinate
     * @param dy destination Y coordinate
     */
    public void blockCopy(int sx, int sy, int w, int h, int dx, int dy) {
        if (sx < 0 || sx + w > mColumns || sy < 0 || sy + h > mScreenRows
                || dx < 0 || dx + w > mColumns || dy < 0
                || dy + h > mScreenRows) {
            throw new IllegalArgumentException();
        }
        if (sy > dy) {
            // Move in increasing order
            for (int y = 0; y < h; y++) {
                int srcOffset = getOffset(sx, sy + y);
                int dstOffset = getOffset(dx, dy + y);
                System.arraycopy(mData, srcOffset, mData, dstOffset, w);
            }
        } else {
            // Move in decreasing order
            for (int y = 0; y < h; y++) {
                int y2 = h - (y + 1);
                int srcOffset = getOffset(sx, sy + y2);
                int dstOffset = getOffset(dx, dy + y2);
                System.arraycopy(mData, srcOffset, mData, dstOffset, w);
            }
        }
    }

    /**
     * Block set characters. All characters must be within the bounds of the
     * screen, or else and InvalidParemeterException will be thrown. Typically
     * this is called with a "val" argument of 32 to clear a block of
     * characters.
     *
     * @param sx source X
     * @param sy source Y
     * @param w width
     * @param h height
     * @param val value to set.
     */
    public void blockSet(int sx, int sy, int w, int h, int val,
            int foreColor, int backColor) {
        if (sx < 0 || sx + w > mColumns || sy < 0 || sy + h > mScreenRows) {
            throw new IllegalArgumentException();
        }
        char[] data = mData;
        char encodedVal = encode(val, foreColor, backColor);
        for (int y = 0; y < h; y++) {
            int offset = getOffset(sx, sy + y);
            for (int x = 0; x < w; x++) {
                data[offset + x] = encodedVal;
            }
        }
    }

    /**
     * Draw a row of text. Out-of-bounds rows are blank, not errors.
     *
     * @param row The row of text to draw.
     * @param canvas The canvas to draw to.
     * @param x The x coordinate origin of the drawing
     * @param y The y coordinate origin of the drawing
     * @param renderer The renderer to use to draw the text
     * @param cx the cursor X coordinate, -1 means don't draw it
     * @param selx1 the text selection start X coordinate
     * @param selx2 the text selection end X coordinate, if equals to selx1 don't draw selection
     * @param imeText current IME text, to be rendered at cursor
     */
    public final void drawText(int row, Canvas canvas, float x, float y,
            TextRenderer renderer, int cx, int selx1, int selx2, String imeText) {

        // Out-of-bounds rows are blank.
        if (row < -mActiveTranscriptRows || row >= mScreenRows) {
            return;
        }

        // Copy the data from the byte array to a char array so they can
        // be drawn.

        int offset = getOffset(row);
        char[] rowBuffer = mRowBuffer;
        char[] data = mData;
        int columns = mColumns;
        int lastColors = 0;
        int lastRunStart = -1;
        final int CURSOR_MASK = 0x10000;
        for (int i = 0; i < columns; i++) {
            char c = data[offset + i];
            int colors = (char) (c & 0xff00);
            if (cx == i || (i >= selx1 && i <= selx2)) {
                // Set cursor background color:
                colors |= CURSOR_MASK;
            }
            rowBuffer[i] = (char) (c & 0x00ff);
            if (colors != lastColors) {
                if (lastRunStart >= 0) {
                    renderer.drawTextRun(canvas, x, y, lastRunStart, rowBuffer,
                            lastRunStart, i - lastRunStart,
                            (lastColors & CURSOR_MASK) != 0,
                            0xf & (lastColors >> 12), 0xf & (lastColors >> 8));
                }
                lastColors = colors;
                lastRunStart = i;
            }
        }
        if (lastRunStart >= 0) {
            renderer.drawTextRun(canvas, x, y, lastRunStart, rowBuffer,
                    lastRunStart, columns - lastRunStart,
                    (lastColors & CURSOR_MASK) != 0,
                    0xf & (lastColors >> 12), 0xf & (lastColors >> 8));
        }

        if (cx >= 0 && imeText.length() > 0) {
            int imeLength = Math.min(columns, imeText.length());
            int imeOffset = imeText.length() - imeLength;
            int imePosition = Math.min(cx, columns - imeLength);
            renderer.drawTextRun(canvas, x, y, imePosition, imeText.toCharArray(),
                    imeOffset, imeLength, true, 0x0f, 0x00);
        }
     }

    /**
     * Get the count of active rows.
     *
     * @return the count of active rows.
     */
    public int getActiveRows() {
        return mActiveRows;
    }

    /**
     * Get the count of active transcript rows.
     *
     * @return the count of active transcript rows.
     */
    public int getActiveTranscriptRows() {
        return mActiveTranscriptRows;
    }

    public String getTranscriptText() {
        return internalGetTranscriptText(true, 0, -mActiveTranscriptRows, mColumns, mScreenRows);
    }

    public String getSelectedText(int selX1, int selY1, int selX2, int selY2) {
        return internalGetTranscriptText(true, selX1, selY1, selX2, selY2);
    }

    private String internalGetTranscriptText(boolean stripColors, int selX1, int selY1, int selX2, int selY2) {
        StringBuilder builder = new StringBuilder();
        char[] rowBuffer = mRowBuffer;
        char[] data = mData;
        int columns = mColumns;
        for (int row = -mActiveTranscriptRows; row < mScreenRows; row++) {
            int offset = getOffset(row);
            int lastPrintingChar = -1;
            for (int column = 0; column < columns; column++) {
                char c = data[offset + column];
                if (stripColors) {
                    c = (char) (c & 0xff);
                }
                if ((c & 0xff) != ' ') {
                    lastPrintingChar = column;
                }
                rowBuffer[column] = c;
            }
            if ( row >= selY1 && row <= selY2 ) {
                int x1 = 0;
                int x2 = 0;
                if ( row == selY1 ) {
                    x1 = selX1;
                }
                if ( row == selY2 ) {
                    x2 = selX2;
                } else {
                    x2 = columns;
                }
                if (mLineWrap[externalToInternalRow(row)]) {
                    builder.append(rowBuffer, x1, x2 - x1);
                } else {
                    builder.append(rowBuffer, x1, Math.max(0, Math.min(x2 - x1 + 1, lastPrintingChar + 1 - x1)));
                    builder.append('\n');
                }
            }
        }
        return builder.toString();
    }

    public void resize(int columns, int rows, int foreColor, int backColor) {
        init(columns, mTotalRows, rows, foreColor, backColor);
    }
}

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