pdfstreamengine.java

非常有用的操作pdf文件的java源码

        int codeLength = 1;
        Matrix ctm = graphicsState.getCurrentTransformationMatrix();
        
        //lets see what the space displacement should be
        spaceDisplacement = (font.getFontWidth( SPACE_BYTES, 0, 1 )/glyphSpaceToTextSpaceFactor);
        if( spaceDisplacement == 0 )
        {
            spaceDisplacement = (averageWidth/glyphSpaceToTextSpaceFactor);
            //The average space width appears to be higher than necessary
            //so lets make it a little bit smaller.
            spaceDisplacement *= .80f;
        }
        int pageRotation = page.findRotation();
        Matrix trm = initialMatrix.multiply( textMatrix ).multiply( ctm );
        float x = trm.getValue(2,0);
        float y = trm.getValue(2,1);
        if( pageRotation == 0 )
        {
            trm.setValue( 2,1, -y + page.findMediaBox().getHeight() );
        }
        else if( pageRotation == 90 )
        {
            trm.setValue( 2,0, y );
            trm.setValue( 2,1, x );
        }
        else if( pageRotation == 270 )
        {
            trm.setValue( 2,0, -y  + page.findMediaBox().getHeight() );
            trm.setValue( 2,1, x );
        }
        for( int i=0; i<string.length; i+=codeLength )
        {
            codeLength = 1;

            String c = font.encode( string, i, codeLength );
            if( c == null && i+1<string.length)
            {
                //maybe a multibyte encoding
                codeLength++;
                c = font.encode( string, i, codeLength );
            }
            stringResult.append( c );

            //todo, handle horizontal displacement
            characterHorizontalDisplacement += (font.getFontWidth( string, i, codeLength )/glyphSpaceToTextSpaceFactor);
            characterVerticalDisplacement = 
                Math.max( 
                    characterVerticalDisplacement, 
                    font.getFontHeight( string, i, codeLength)/glyphSpaceToTextSpaceFactor);


            // PDF Spec - 5.5.2 Word Spacing
            //
            // Word spacing works the same was as character spacing, but applies
            // only to the space character, code 32.
            //
            // Note: Word spacing is applied to every occurrence of the single-byte
            // character code 32 in a string.  This can occur when using a simple
            // font or a composite font that defines code 32 as a single-byte code.
            // It does not apply to occurrences of the byte value 32 in multiple-byte
            // codes.
            //
            // RDD - My interpretation of this is that only character code 32's that
            // encode to spaces should have word spacing applied.  Cases have been
            // observed where a font has a space character with a character code
            // other than 32, and where word spacing (Tw) was used.  In these cases,
            // applying word spacing to either the non-32 space or to the character
            // code 32 non-space resulted in errors consistent with this interpretation.
            //
            if( (string[i] == 0x20) && c.equals( " " ) )
            {
                spacing += wordSpacing + characterSpacing;
            }
            else
            {
                spacing += characterSpacing;
            }
            // We want to update the textMatrix using the width, in text space units.
            //
            
        }
        
        //The adjustment will always be zero.  The adjustment as shown in the
        //TJ operator will be handled separately.
        float adjustment=0;
        //todo, need to compute the vertical displacement
        float ty = 0;
        float tx = ((characterHorizontalDisplacement-adjustment/glyphSpaceToTextSpaceFactor)*fontSize + spacing)
                   *horizontalScaling;
        
        float xScale = trm.getXScale();
        float yScale = trm.getYScale(); 
        float xPos = trm.getXPosition();
        float yPos = trm.getYPosition();
        spaceWidth = spaceDisplacement * xScale * fontSize;
        wordSpacingDisplacement = wordSpacing*xScale * fontSize;
        Matrix td = new Matrix();
        td.setValue( 2, 0, tx );
        td.setValue( 2, 1, ty );            
        
        float xPosBefore = textMatrix.getXPosition();
        float yPosBefore = textMatrix.getYPosition();
        textMatrix = td.multiply( textMatrix );

        float totalStringWidth = 0;
        float totalStringHeight = characterVerticalDisplacement * fontSize * yScale;
        if( pageRotation == 0 )
        {
            totalStringWidth = (textMatrix.getXPosition() - xPosBefore);
        }
        else if( pageRotation == 90 )
        {
            totalStringWidth = (textMatrix.getYPosition() - yPosBefore);
        }
        else if( pageRotation == 270 )
        {
            totalStringWidth = (yPosBefore - textMatrix.getYPosition());
        }
        showCharacter(
                new TextPosition(
                    xPos,
                    yPos,
                    xScale,
                    yScale,
                    totalStringWidth,
                    totalStringHeight,
                    spaceWidth,
                    stringResult.toString(),
                    font,
                    fontSize,
                    wordSpacingDisplacement ));
    }
    
    /**
     * This is used to handle an operation.
     *
     * @param operation The operation to perform.
     * @param arguments The list of arguments.
     *
     * @throws IOException If there is an error processing the operation.
     */
    public void processOperator( String operation, List arguments ) throws IOException
    {
        PDFOperator oper = PDFOperator.getOperator( operation );
        processOperator( oper, arguments );
    }

    /**
     * This is used to handle an operation.
     *
     * @param operator The operation to perform.
     * @param arguments The list of arguments.
     *
     * @throws IOException If there is an error processing the operation.
     */
    protected void processOperator( PDFOperator operator, List arguments ) throws IOException
    {
        String operation = operator.getOperation();
        OperatorProcessor processor = (OperatorProcessor)operators.get( operation );
        if( processor != null )
        {
            processor.process( operator, arguments );
        }
    } 
   
    /**
     * @return Returns the colorSpaces.
     */
    public Map getColorSpaces() 
    {
        return ((StreamResources) streamResourcesStack.peek()).colorSpaces;
    }
    
    /**
     * @return Returns the colorSpaces.
     */
    public Map getXObjects() 
    {
        return ((StreamResources) streamResourcesStack.peek()).xobjects;
    }
    
    /**
     * @param value The colorSpaces to set.
     */
    public void setColorSpaces(Map value) 
    {
        ((StreamResources) streamResourcesStack.peek()).colorSpaces = value;
    }
    /**
     * @return Returns the fonts.
     */
    public Map getFonts() 
    {
        return ((StreamResources) streamResourcesStack.peek()).fonts;
    }
    /**
     * @param value The fonts to set.
     */
    public void setFonts(Map value) 
    {
        ((StreamResources) streamResourcesStack.peek()).fonts = value;
    }
    /**
     * @return Returns the graphicsStack.
     */
    public Stack getGraphicsStack() 
    {
        return graphicsStack;
    }
    /**
     * @param value The graphicsStack to set.
     */
    public void setGraphicsStack(Stack value) 
    {
        graphicsStack = value;
    }
    /**
     * @return Returns the graphicsState.
     */
    public PDGraphicsState getGraphicsState() 
    {
        return graphicsState;
    }
    /**
     * @param value The graphicsState to set.
     */
    public void setGraphicsState(PDGraphicsState value) 
    {
        graphicsState = value;
    }
    /**
     * @return Returns the graphicsStates.
     */
    public Map getGraphicsStates() 
    {
        return ((StreamResources) streamResourcesStack.peek()).graphicsStates;
    }
    /**
     * @param value The graphicsStates to set.
     */
    public void setGraphicsStates(Map value) 
    {
        ((StreamResources) streamResourcesStack.peek()).graphicsStates = value;
    }
    /**
     * @return Returns the textLineMatrix.
     */
    public Matrix getTextLineMatrix() 
    {
        return textLineMatrix;
    }
    /**
     * @param value The textLineMatrix to set.
     */
    public void setTextLineMatrix(Matrix value) 
    {
        textLineMatrix = value;
    }
    /**
     * @return Returns the textMatrix.
     */
    public Matrix getTextMatrix() 
    {
        return textMatrix;
    }
    /**
     * @param value The textMatrix to set.
     */
    public void setTextMatrix(Matrix value) 
    {
        textMatrix = value;
    }
    /**
     * @return Returns the resources.
     */
    public PDResources getResources()
    {
        return ((StreamResources) streamResourcesStack.peek()).resources;
    }
    
    /**
     * Get the current page that is being processed.
     * 
     * @return The page being processed.
     */
    public PDPage getCurrentPage()
    {
        return page;
    }
}