The R Project SVN R-packages

//  PDFImageView.m

//  Copyright (c) 2003, Apple Computer, Inc. All rights reserved.

// See legal notice below.

#import "PDFImageView.h"
#import "DraggableScrollView.h"

@implementation PDFImageView

#pragma mark PRIVATE INSTANCE METHODS

//  pdfRep -- Return the image-representation used for PDFs. This
//  representation can tell us things like the PDF's page count.
- (NSPDFImageRep *) pdfRep
{
    //  Assume our sole representation is the PDF representation.
    return [[[self image] representations] lastObject];
}


#pragma mark PUBLIC INSTANCE METHODS

//  loadFromPath: -- Load the PDF at the specified path into the view.
//  This automatically resizes the view to fit all pages of the document.
- (void) loadFromPath: (NSString *) path
{
    NSPDFImageRep   *pdfRep;
    NSImage         *pdfImage;
    NSRect          frame;

    //  Load the file into an image-representation,
    //  then create an image and add the representation to it.
    pdfRep = [NSPDFImageRep imageRepWithContentsOfFile: path];
    pdfImage = [[[NSImage alloc] init] autorelease];
    [pdfImage addRepresentation: pdfRep];

    //  Figure our frame by getting the bounds, which is really the size
    //  of one page, and multiplying the height by the page count.
    frame = [pdfRep bounds];
    frame.size.height *= [pdfRep pageCount];

    //  Install the image (remember, we're an NSImageView subclass)
    [self setImage: pdfImage];

    //  Set our frame to match the PDF's full height (all pages)
    //  (don't involve our override of -setFrame:, or things won't work right)
    [super setFrame: frame];

    //  Always scroll to show the top of the image
    if ([self isFlipped])
        [self scrollPoint: NSMakePoint (0, 0)];
    else
        [self scrollPoint: NSMakePoint (0, frame.size.height)];
}


#pragma mark PUBLIC INSTANCE METHODS -- NSView OVERRIDES

//  drawRect: -- Display all pages of the PDF document.
- (void) drawRect: (NSRect) rect
{
    NSPDFImageRep   *rep;
    int             pageCount, pageNumber;
    NSRect          onePageBounds;

    //  Apparently, a PDF doesn't always draw its margins, so make them white
    //  by drawing our entire background as white.
    [[NSColor whiteColor] set];
    NSRectFill (rect);

    //  Get the information from the PDF image representation:
    //  how many pages, and how large is each one?
    rep = [self pdfRep];
    pageCount = [rep pageCount];

    //  Iterate through all pages
    for (pageNumber = 0; pageNumber < pageCount; pageNumber++)
    {
        //  Use the printing code (which uses one-based numbering) to find where
        //  this page appears.
        onePageBounds = [self rectForPage: (1+pageNumber)];

        //  Draw this page only if some of its bounds overlap the drawing area
        if (! NSIntersectsRect (rect, onePageBounds))
            continue;

        //  Draw by setting the image representation to the correct page,
        //  then having the image representation draw.
        [rep setCurrentPage: pageNumber];
        [rep drawInRect: onePageBounds];
    }
}

//  mouseDown: -- If we have an enclosing scroll-view which knows how to drag,
//  hand the event off to that scroll-view.
- (void) mouseDown:(NSEvent *) theEvent
{
    NSScrollView    *scrollView;

    scrollView = [self enclosingScrollView];

    if ([scrollView respondsToSelector: @selector(dragDocumentWithMouseDown:)])
        [(DraggableScrollView*)scrollView dragDocumentWithMouseDown: theEvent];
    else
        [super mouseDown: theEvent];
}

//  -setFrameSize: -- Override this method to make sure we keep our aspect ratio.
//  This assumes -setFrameSize: is a primitive method (i.e., -setFrame: invokes it)
- (void) setFrameSize: (NSSize) newSize
{
    NSSize  PDFsize;
    float   correctHeight;

    PDFsize = [[self pdfRep] bounds].size;
    correctHeight = [[self pdfRep] pageCount] * (PDFsize.height/PDFsize.width) * newSize.width;
    correctHeight = ceil (correctHeight); // not sure we need this

    //  If the height's almost right, don't fuss with it.
    if (abs (correctHeight - newSize.height) > 3.0)
        newSize.height = correctHeight;

    [super setFrameSize: newSize];
}


#pragma mark PUBLIC INSTANCE METHODS -- NSView OVERRIDES FOR PRINTING

- (BOOL) knowsPageRange: (NSRangePointer) range
{
    range->location = 1;                // page numbers are one-based
    range->length = [[self pdfRep] pageCount];

    return YES;
}

- (NSRect) rectForPage: (NSInteger) pageNumber // INPUT: ONE-based page number
{
    NSPDFImageRep   *rep;
    NSInteger       pageCount;
    NSRect          result;

    rep = [self pdfRep];
    pageCount = [rep pageCount];

    //  Start at the first page
    result = [rep bounds];
    if (! [self isFlipped])
        result = NSOffsetRect (result, 0.0, (pageCount-1) * result.size.height);

    //  Move to the N'th page
    if ([self isFlipped])
        result = NSOffsetRect (result, 0.0, (pageNumber-1) * result.size.height);
    else
        result = NSOffsetRect (result, 0.0, - (pageNumber-1) * result.size.height);

    return result;
}

@end



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