iOS開發之Quartz2D生成PDF-Part2

iOS開發之Quartz2D生成PDF-Part2

在上一節當中，我們創建了一個基於Quartz2D的PDF，並在PDF中添加一線條。
在這一節，主要是添加一個logo，和繪製一個table。

添加logo

下載圖片資源，然後添加到工程當中。

在`PDFRenderer.m`文件中添加下面方法：

//繪製圖像
+ (void)drawImage:(UIImage*)image inRect:(CGRect)rect {
    [image drawInRect:rect];
}

在PDFRenderer.h中添加下面方法：

+ (void)drawImage:(UIImage*)image inRect:(CGRect)rect;

爲了能在PDF上顯示此logo，在PDFRenderer.m的drawPDF方法中添加下面代碼，此代碼寫在UIGraphicsEndPDFContext();之前：

UIImage *logo = [UIImage imageNamed:@"ray-logo"];
    CGRect frame = CGRectMake(20, 100, 300, 60);
    [PDFRenderer drawImage:logo inRect:frame];

在上面的代碼中，創建一個UIImage對象，並定義圖像的位置和大小，調用drawImage方法將兩個參數傳過去進行繪製。

完整代碼如下：

+ (void)drawPDF:(NSString*)fileName {
    UIGraphicsBeginPDFContextToFile(fileName, CGRectZero, nil);
    UIGraphicsBeginPDFPageWithInfo(CGRectMake(0, 0, 612, 792), nil);

    CGPoint from = CGPointMake(0, 0);
    CGPoint to = CGPointMake(200, 300);
    [PDFRenderer drawLineFromPoint:from toPoint:to];

    UIImage *logo = [UIImage imageNamed:@"ray-logo"];
    CGRect frame = CGRectMake(20, 100, 300, 60);
    [PDFRenderer drawImage:logo inRect:frame];

    [self drawText];

    UIGraphicsEndPDFContext();
}

至此瞭解到如何繪製清單的基本元素：文本、線條、圖片。接下來將運用這些所有元素構建更爲完美的佈局。

繪製Labels

創建一個xib，並命名爲InvoiceView，選中InvoiceViewIB，設置View的width: 612 和height: 792，這些都是A4PDF的默認尺寸。下面拖拽8個UILabel，並按如下命名：

• Recipient [Name]
• Recipient’s Address
• Recipient’s City
• Recipient’s Postal Code
• Invoicer [Name]
• Invoicer’s Address
• Invoicer’s City
• Invoicer’s Postal Code

這些labels的位置將會在PDF上進行佈局。給每個label從0-7設置tag。例如：Recipient的tag是0，Recipient’s Address的tag事1，以此類推。

打開PDFRenderer.m文件，並重構drawText方法。代碼清單如下：

+(void)drawText:(NSString*)textToDraw inFrame:(CGRect)frameRect {

    CFStringRef stringRef = (__bridge CFStringRef)textToDraw;
    CFAttributedStringRef currentText = CFAttributedStringCreate(NULL, stringRef, NULL);
    CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString(currentText);

    CGMutablePathRef framePath = CGPathCreateMutable();
    CGPathAddRect(framePath, NULL, frameRect);
    CFRange currentRange = CFRangeMake(0, 0);
    CTFrameRef frameRef = CTFramesetterCreateFrame(framesetter, currentRange, framePath, NULL);
    CGPathRelease(framePath);

    CGContextRef currentContext = UIGraphicsGetCurrentContext();

    CGContextSetTextMatrix(currentContext, CGAffineTransformIdentity);

    CGContextTranslateCTM(currentContext, 0,100);
    CGContextScaleCTM(currentContext, 1.0, -1.0);

    CTFrameDraw(frameRef, currentContext);

    CFRelease(frameRef);
    CFRelease(stringRef);
    CFRelease(framesetter);
}

在PDFRenderer.h文件中添加下面代碼：

+(void)drawText:(NSString*)textToDraw inFrame:(CGRect)frameRect

下面是從InvoiceView中加載label，使用文本和位置大小來繪製到PDF上。在PDFRenderer.m中的drawPDF的商法添加一個新方法drawLabels:

+ (void)drawLabels {
    NSArray *objects = [[NSBundle mainBundle] loadNibNamed:@"InvoiceView" owner:nil options:nil];
    UIView *mainView = [objects lastObject];
    for (UIView *view in [mainView subviews]) {
        if ([view isKindOfClass:[UILabel class]]) {
            UILabel *label = (UILabel*)view;
            [self drawText:label.text inFrame:label.frame];
        }
    }
}

這個方法是加載InvoiceView，遍歷InvoiceView中的labels，調用drawText，將text和frame變量傳遞過去。

需改drawPDF方法：

+ (void)drawPDF:(NSString*)fileName {
    UIGraphicsBeginPDFContextToFile(fileName, CGRectZero, nil);
    UIGraphicsBeginPDFPageWithInfo(CGRectMake(0, 0, 612, 792), nil);

    [self drawText:@"Hello world" inFrame:CGRectMake(0, 0, 300, 50)];

    [self drawLabels];
//    [self drawText];

    UIGraphicsEndPDFContext();
}

運行下模擬器：

啊哈，能運行出來，但結果不是令人滿意，文字啥的都是反的。接下來就坐下處理，修改drawText 的代碼：

CGContextTranslateCTM(currentContext, 0, frameRect.origin.y*2);
    CGContextScaleCTM(currentContext, 1.0, -1.0);

    CTFrameDraw(frameRef, currentContext);

    CGContextScaleCTM(currentContext, 1.0, -1.0);
    CGContextTranslateCTM(currentContext, 0, (-1.0) * frameRect.origin.y * 2);

再次運行下模擬器，看下結果：

結果比較令人滿意。

添加logo

打開InvoiceView.xib 添加一個UIImageView

然後在PDFRenderer.m 中添加drawLogo方法:

+ (void)drawLogo {
    NSArray *objects = [[NSBundle mainBundle] loadNibNamed:@"InvoiceView" owner:nil options:nil];
    UIView *mainView = [objects lastObject];
    for (UIView *view in [mainView subviews]) {
        if ([view isKindOfClass:[UIImageView class]]) {
            UIImage *logo = [UIImage imageNamed:@"ray-logo"];
            [self drawImage:logo inRect:view.frame];
        }
    }
}

處理邏輯和drawLabels 方法類似。

最後在drawPDF 方法中的[self drawLabels] 語句後調用[self drawLogo] 。來看下運行效果：

繪製一個表格

繪製表格不能像使用InvoiceView 那樣，需要一系列的變量來替代，例如：table的width和height，row的height，column的width。

下面在PDFRenderer.m 的drawPDF 上方添加如下代碼：

+ (void)drawTableAt:(CGPoint)origin
      withRowHeight:(int)rowHeight
     andColumnWidth:(int)columnWidth
        andRowCount:(int)numberOfRows
     andColumnCount:(int)numberOfColumns
{
    for (int i = 0; i <= numberOfRows; i++) {
        int newOrigin = origin.y + (rowHeight * i);

        CGPoint from = CGPointMake(origin.x, newOrigin);
        CGPoint to = CGPointMake(origin.x + (numberOfColumns*columnWidth), newOrigin);

        [self drawLineFromPoint:from toPoint:to];
    }
}

上面方法是繪製水平線，循環遍歷每一行，計算每行的起始和結束位置。最後調用drawLine:from:to 方法繪製水平線：

+ (void)drawPDF:(NSString*)fileName {
    UIGraphicsBeginPDFContextToFile(fileName, CGRectZero, nil);
    UIGraphicsBeginPDFPageWithInfo(CGRectMake(0, 0, 612, 792), nil);

    [self drawText:@"Hello world" inFrame:CGRectMake(0, 0, 300, 50)];

    [self drawLabels];
    [self drawLogo];


    int xOrigin = 50;
    int yOrigin = 300;
    int rowHeight = 50;
    int columnWidth = 120;
    int numberOfRows = 7;
    int numberOfColumns = 4;

    [self drawTableAt:CGPointMake(xOrigin, yOrigin)
        withRowHeight:rowHeight
       andColumnWidth:columnWidth
          andRowCount:numberOfRows
       andColumnCount:numberOfColumns];

    UIGraphicsEndPDFContext();
}

運行模擬器，看下效果：

接下來是繪製垂直線條，在drawTable 方法中的第一個循環的下方再添加一個循環：

+ (void)drawTableAt:(CGPoint)origin
      withRowHeight:(int)rowHeight
     andColumnWidth:(int)columnWidth
        andRowCount:(int)numberOfRows
     andColumnCount:(int)numberOfColumns
{
    //繪製水平線
    for (int i = 0; i <= numberOfRows; i++) {
        int newOrigin = origin.y + (rowHeight * i);

        CGPoint from = CGPointMake(origin.x, newOrigin);
        CGPoint to = CGPointMake(origin.x + (numberOfColumns*columnWidth), newOrigin);

        [self drawLineFromPoint:from toPoint:to];
    }

    //繪製垂直線
    for (int i = 0; i <= numberOfColumns; i++) {
        int newOrigin = origin.x + (columnWidth * i);
        CGPoint from = CGPointMake(newOrigin, origin.y);
        CGPoint to = CGPointMake(newOrigin, origin.y + (numberOfRows * rowHeight));

        [self drawLineFromPoint:from toPoint:to];
    }
}

再次運行下模擬器，看下效果：

看着似乎已完成，但還缺少一些數據填充到表格當中，那麼接下來完成此過程，讓此PDF近乎完美。

填充表格

模擬數據填充表格，在PDFRenderer.m 中的drawPDF 方法的上方添加 drawTableDataAt 方法:

+ (void)drawTableDataAt:(CGPoint)origin
          withRowHeight:(int)rowHeight
         andColumnWidth:(int)columnWidth
            andRowCount:(int)numberOfRows
         andColumnCount:(int)numberOfColumns
{
    NSArray *header = @[@"Quantity", @"Description", @"Unit price", @"Total"];
    NSArray *invoiceInfo1 = @[@"1", @"Development", @"$1000", @"1000"];
    NSArray *invoiceInfo2 = @[@"1", @"Development", @"$1000", @"1000"];
    NSArray *invoiceInfo3 = @[@"1", @"Development", @"$1000", @"1000"];
    NSArray *invoiceInfo4 = @[@"1", @"Development", @"$1000", @"1000"];

    NSArray *allInfo = @[header, invoiceInfo1, invoiceInfo2, invoiceInfo3, invoiceInfo4];

    for (int i = 0; i < allInfo.count; i++) {
        NSArray *infoToDraw = allInfo[i];
        for (int j = 0; j< numberOfColumns; j++) {
            int newOriginX = origin.x + (columnWidth * j);
            int newOriginY = origin.y + (rowHeight * (i+1));

            CGRect frame = CGRectMake(newOriginX, newOriginY, columnWidth, rowHeight);
            [self drawText:infoToDraw[j] inFrame:frame];
        }
    }
}

第一個數組是表頭數據，其他數組是表中行和列的值。

在drawPDF 中調用drawTableDataAt（在UIGraphicsEndPDFContext 之前調用）：

[self drawTableDataAt:CGPointMake(xOrigin, yOrigin)
            withRowHeight:rowHeight
           andColumnWidth:columnWidth
              andRowCount:numberOfRows
           andColumnCount:numberOfColumns];

運行模擬器，將會看到表中填充的數據:

感覺還差點什麼，再做最後一次調整：添加間距padding

+ (void)drawTableDataAt:(CGPoint)origin
          withRowHeight:(int)rowHeight
         andColumnWidth:(int)columnWidth
            andRowCount:(int)numberOfRows
         andColumnCount:(int)numberOfColumns
{
    int padding = 10;
    NSArray *header = @[@"Quantity", @"Description", @"Unit price", @"Total"];
    NSArray *invoiceInfo1 = @[@"1", @"Development", @"$1000", @"1000"];
    NSArray *invoiceInfo2 = @[@"1", @"Development", @"$1000", @"1000"];
    NSArray *invoiceInfo3 = @[@"1", @"Development", @"$1000", @"1000"];
    NSArray *invoiceInfo4 = @[@"1", @"Development", @"$1000", @"1000"];

    NSArray *allInfo = @[header, invoiceInfo1, invoiceInfo2, invoiceInfo3, invoiceInfo4];

    for (int i = 0; i < allInfo.count; i++) {
        NSArray *infoToDraw = allInfo[i];
        for (int j = 0; j< numberOfColumns; j++) {
            int newOriginX = origin.x + (columnWidth * j);
            int newOriginY = origin.y + (rowHeight * (i+1));

            CGRect frame = CGRectMake(newOriginX+padding, newOriginY+padding, columnWidth, rowHeight);
            [self drawText:infoToDraw[j] inFrame:frame];
        }
    }
}

最終結果：

大功告成，此PDF主要展示了圖片、表格和數據。