This article shows how to draw thumbnails with page number:

In PDFVCanvas class, add the following method:

-(void)DrawThumbBmp:(PDFDIB *)dib :(int)x :(int)y :(int)page

{

    NSString *opage = [NSString stringWithFormat:@"%i", page + 1];

    Byte *data = (Byte *)[dib data];

    int w = [dib width];

    int h = [dib height];

    CGDataProviderRef provider = CGDataProviderCreateWithData( NULL, data, w * h * 4, NULL );

    CGColorSpaceRef cs = CGColorSpaceCreateDeviceRGB();

    CGImageRef img = CGImageCreate( w, h, 8, 32, w<<2, cs, kCGBitmapByteOrder32Little|kCGImageAlphaNoneSkipFirst, provider, NULL, FALSE, kCGRenderingIntentDefault );

    CGColorSpaceRelease(cs);

    CGDataProviderRelease(provider);

    CGContextSaveGState(m_ctx);

    float tmp = 1/m_scale;

    CGContextTranslateCTM(m_ctx, x * tmp, (y + h) * tmp);

    CGContextScaleCTM(m_ctx, tmp, -tmp);

    CGContextDrawImage(m_ctx, CGRectMake(0, 0, w, h), img);

    // Add the page number

    NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];

    [paragraphStyle setAlignment:NSTextAlignmentCenter];

    CGContextTranslateCTM(m_ctx, 0.0f, h);

    CGContextScaleCTM(m_ctx, 1.0f, -1.0f);

    // Set font and color

    [opage drawInRect:CGRectMake(0, h/2 - h/5, w, h/5) withAttributes:@{NSFontAttributeName: [UIFont fontWithName:@"Helvetica" size:h/5], NSForegroundColorAttributeName: [UIColor colorWithRed:1.0f green:0.0f blue:0.0f alpha:1.0f], NSParagraphStyleAttributeName: paragraphStyle}];

    CGContextRestoreGState(m_ctx);

    CGImageRelease(img);

}

Edit DrawThumb method of PDFVPage class to use the new method instead of DrawBmp:

-(void)DrawThumb:(PDFVCanvas *)canvas

{

    if( m_thumb != nil && [m_thumb Bmp] != nil )

        [canvas DrawThumbBmp:[m_thumb Bmp] :m_x :m_y :m_pageno]; // New method

    else

        [canvas FillRect: CGRectMake(m_x, m_y, m_w, m_h): 0xFFFFFFFF];

    if( m_sel != nil )

        [m_sel DrawSel:canvas: m_scale: [m_doc pageHeight:m_pageno]: m_x: m_y];

}