/*

 File: AppDrawing.c

 Abstract: Sample Quartz drawing code.

 Version: <1.0>

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*/  

#include "AppDrawing.h"

#include "UIHandling.h"

#include "math.h"

/* Defines */

#define kOurImageFile       CFSTR("ptlobos.tif")

// For best performance make bytesPerRow a multiple of 16 bytes.

#define BEST_BYTE_ALIGNMENT 16

#define COMPUTE_BEST_BYTES_PER_ROW(bpr)     ( ( (bpr) + (BEST_BYTE_ALIGNMENT-1) ) & ~(BEST_BYTE_ALIGNMENT-1) )

/* Prototypes */

static void drawStrokedAndFilledRects(CGContextRef context);

static void drawAlphaRects(CGContextRef context);

static void drawCGImage(CGContextRef context, CFURLRef url);

static void clipImageToEllipse(CGContextRef context, CFURLRef url);

static void drawSimpleCGLayer(CGContextRef context);

static void drawUncachedForLayer(CGContextRef context);

static inline float DEGREES_TO_RADIANS(float degrees){

    return degrees * M_PI/180;

}

static CGColorSpaceRef myGetGenericRGBSpace(void)

{

    // Only create the color space once.

    static CGColorSpaceRef colorSpace = NULL;

    if ( colorSpace == NULL ) {

    colorSpace = CGColorSpaceCreateWithName(kCGColorSpaceGenericRGB);

    }

    return colorSpace;

}

static CGColorRef myGetBlueColor(void)

{

    // Only create the CGColor object once.

    static CGColorRef blue = NULL;

    if(blue == NULL){

    // R,G,B,A

    float opaqueBlue[4] = { 0, 0, 1, 1 };

    blue = CGColorCreate(myGetGenericRGBSpace(), opaqueBlue);

    }

    return blue;

}

static CGColorRef myGetGreenColor(void)

{

    // Only create the CGColor object once.

    static CGColorRef green = NULL;

    if(green == NULL){

    // R,G,B,A

    float opaqueGreen[4] = { 0, 1, 0, 1 };

    green = CGColorCreate(myGetGenericRGBSpace(), opaqueGreen);

    }

    return green;

}

static CGColorRef myGetRedColor(void)

{

    // Only create the CGColor object once.

    static CGColorRef red = NULL;

    if(red == NULL){

    // R,G,B,A

    float opaqueRed[4] = { 1, 0, 0, 1 };

    red = CGColorCreate(myGetGenericRGBSpace(), opaqueRed);

    }

    return red;

}

static void doDrawImageFile(CGContextRef context, Boolean doclip)

{

    // Only get the image URL the first time the function is called.

    static CFURLRef ourImageURL = NULL;

    if(ourImageURL == NULL){

    CFBundleRef mainBundle = CFBundleGetMainBundle();

    if(mainBundle){

        ourImageURL = CFBundleCopyResourceURL(mainBundle, kOurImageFile, NULL, NULL);

    }else{

        fprintf(stderr, "Can't get the app bundle!\n");

    }

    }

    if(ourImageURL){

    doclip ? clipImageToEllipse(context, ourImageURL) : drawCGImage(context, ourImageURL);

    }else{

    fprintf(stderr, "Couldn't create the URL for our Image file!\n");

    }

}

/* Dispatch Drawing */

void myDispatchDrawing(CGContextRef context, OSType drawingType)

{

    switch (drawingType){

    case kCommandStrokedAndFilledRects:

        drawStrokedAndFilledRects(context);

        break;

    case kCommandAlphaRects:

        drawAlphaRects(context);

        break;

    case kCommandSimpleClip:

        doDrawImageFile(context, true);

        break;

    case kCommandDrawImageFile:

        doDrawImageFile(context, false);

        break;

    case kCommandDoUncachedDrawing:

        drawUncachedForLayer(context);

        break;

    case kCommandDoCGLayer:

        drawSimpleCGLayer(context);

        break;

    default:

        break;

    }

}

void drawStrokedAndFilledRects(CGContextRef context)

{

    // Make a CGRect that has its origin at (40,40)

    // with a width of 130 units and height of 100 units.

    CGRect ourRect = CGRectMake(40, 40, 130, 100);

    // Set the fill color to an opaque blue.

    CGContextSetFillColorWithColor(context, myGetBlueColor());

    // Fill the rect.

    CGContextFillRect(context, ourRect);

    // Set the stroke color to an opaque green.

    CGContextSetStrokeColorWithColor(context, myGetGreenColor());

    // Stroke the rect with a line width of 10 units.

    CGContextStrokeRectWithWidth(context, ourRect, 10);

    // Save the current graphics state.

    CGContextSaveGState(context);

        // Translate the coordinate system origin to the right 

        // by 200 units.

        CGContextTranslateCTM(context, 200, 0);

        // Stroke the rect with a line width of 10 units.

        CGContextStrokeRectWithWidth(context, ourRect, 10);

        // Fill the rect.

        CGContextFillRect(context, ourRect);

    // Restore the graphics state to the previously saved

    // graphics state. This restores all graphics state

    // parameters to those in effect during the last call

    // to CGContextSaveGState. In this example that restores

    // the coordinate system to that in effect prior to the

    // call to CGContextTranslateCTM.

    CGContextRestoreGState(context);

}

/*

    Create a mutable path object that represents 'rect'.

    Note that this is for demonstrating how to create a simple

    CGPath object. The Quartz function CGPathAddRect would normally

    be a better choice for adding a rect to a CGPath object.

*/

static CGPathRef createRectPath(CGRect rect)

{

    CGMutablePathRef path = CGPathCreateMutable();

    // Start a new subpath.

    CGPathMoveToPoint(path, NULL, rect.origin.x, rect.origin.y);

    // ***** Segment 1 *****

    CGPathAddLineToPoint(path, NULL,  rect.origin.x + rect.size.width, rect.origin.y);

    // ***** Segment 2 *****

    CGPathAddLineToPoint(path, NULL, rect.origin.x + rect.size.width,

             rect.origin.y + rect.size.height);

    // ***** Segment 3 *****

    CGPathAddLineToPoint(path, NULL, rect.origin.x, rect.origin.y + rect.size.height);

    // ***** Segment 4 is created by closing the path *****

    CGPathCloseSubpath(path);

    return path;

}

static void drawAlphaRects(CGContextRef context)

{

    CGRect ourRect = CGRectMake(0, 0, 130, 100);

    int numRects = 6;

    float rotateAngle = 2*M_PI/numRects;

    float tint, tintAdjust = 1.0/numRects;

    /*  Create the path object representing our rectangle. This

    example is for demonstrating the use of a CGPath object.

    For a simple rectangular shape, you'd typically use

    CGContextFillRect or CGContextStrokeRect instead of this

    approach.

    */

    CGPathRef path = createRectPath(ourRect);

    // Move the origin of coordinates to a location that allows

    // the drawing to be within the window.

    CGContextTranslateCTM(context, 2*ourRect.size.width, 

               2*ourRect.size.height);

    // Set the fill color to a red color.

    CGContextSetFillColorWithColor(context, myGetRedColor());

    for(tint = 1.0;  0 < tint ; tint -= tintAdjust){

    // Set the global alpha to the tint value.

    CGContextSetAlpha(context, tint);

    // For a CGPath object that is a simple rect, 

    // this is equivalent to CGContextFillRect.

    CGContextBeginPath(context);

    CGContextAddPath(context, path);

    CGContextFillPath(context);

    // These transformations are cummulative.

    CGContextRotateCTM(context, rotateAngle);

    }

    // Release the CGPath object when finished with it.

    CGPathRelease(path);

}

static void drawCGImage(CGContextRef context, CFURLRef url)

{

    // Create a CGImageSource object from 'url'.

    CGImageSourceRef imageSource =  CGImageSourceCreateWithURL(url, NULL);

    // Create a CGImage object from the first image in the file. Image

    // indexes are 0 based.

    CGImageRef image = CGImageSourceCreateImageAtIndex( imageSource, 0, NULL );

    // Now that we've created the CGImage object, the imageSource is no longer

    // needed so release it. CGImageSource objects are CF objects so they are

    // released with CFRelease.

    CFRelease(imageSource);

    // Create a rectangle that has its origin at (100, 100) with the width

    // and height of the image itself.

    CGRect imageRect = CGRectMake(100, 100, CGImageGetWidth(image), CGImageGetHeight(image));

    // Draw the image into the rect.

    CGContextDrawImage(context, imageRect, image);

    // Release the image object we created. In Mac OS X v10.2 and later, CG objects

    // are CF objects so you can use CFRelease to release them. Image objects can also 

    // be released with CGImageRelease. 

    CFRelease(image);

}

static void clipImageToEllipse(CGContextRef context, CFURLRef url)

{

    // Create a CGImageSource object from 'url'.

    CGImageSourceRef imageSource =  CGImageSourceCreateWithURL(url, NULL);

    // Create a CGImage object from the first image in the file. Image

    // indexes are 0 based.

    CGImageRef image = CGImageSourceCreateImageAtIndex( imageSource, 0, NULL );

    // Now that we've created the CGImage object, the imageSource is no longer

    // needed so release it. CGImageSource objects are CF objects so they are

    // released with CFRelease.

    CFRelease(imageSource);

    // Create a rectangle that has its origin at (100, 100) with the width

    // and height of the image itself.

    CGRect imageRect = CGRectMake(100, 100, CGImageGetWidth(image), CGImageGetHeight(image));

    CGContextBeginPath(context);

    // Create an elliptical path corresponding to the image width and height.

    CGContextAddEllipseInRect(context, imageRect);

    // Clip to the current path.

    CGContextClip(context);

    // Draw the image into the rect, clipped by the ellipse.

    CGContextDrawImage(context, imageRect, image);

    // Release the image object we created. In Mac OS X v10.2 and later, CG objects

    // are CF objects so you can use CFRelease to release them. Image objects can also 

    // be released with CGImageRelease. 

    CFRelease(image);

}

static CGImageRef createRGBAImageFromQuartzDrawing(float dpi, OSType drawingCommand)

{

    // For generating RGBA data from drawing. Use a Letter size page as the 

    // image dimensions. Typically this size would be the minimum necessary to 

    // capture the drawing of interest. We want 8 bits per component and for

    // RGBA data there are 4 components.

    size_t width = 8.5*dpi, height = 11*dpi, bitsPerComponent = 8, numComps = 4;

    // Compute the minimum number of bytes in a given scanline.

    size_t bytesPerRow = width* bitsPerComponent/8 * numComps;

    // This bitmapInfo value specifies that we want the format where alpha is

    // premultiplied and is the last of the components. We use this to produce

    // RGBA data.

    CGBitmapInfo bitmapInfo = kCGImageAlphaPremultipliedLast;

    // Round to nearest multiple of BEST_BYTE_ALIGNMENT for optimal performance.

    bytesPerRow = COMPUTE_BEST_BYTES_PER_ROW(bytesPerRow);

    // Allocate the data for the bitmap.

    char *data = malloc( bytesPerRow * height );

    // Create the bitmap context. Characterize the bitmap data with the

    // Generic RGB color space.

    CGContextRef bitmapContext = CGBitmapContextCreate( 

            data, width, height, bitsPerComponent, bytesPerRow,

            myGetGenericRGBSpace(), bitmapInfo);

    // Clear the destination bitmap so that it is completely transparent before

    // performing any drawing. This is appropriate for exporting PNG data or

    // other data formats that capture alpha data. If the destination output

    // format doesn't support alpha then a better choice would be to paint

    // to white.

    CGContextClearRect( bitmapContext, CGRectMake(0, 0, width, height) );

    // Scale the coordinate system so that 72 units are dpi pixels.

    CGContextScaleCTM( bitmapContext, dpi/72, dpi/72 );

    // Perform the requested drawing.

    myDispatchDrawing(bitmapContext, drawingCommand);

    // Create a CGImage object from the drawing performed to the bitmapContext.

    CGImageRef image = CGBitmapContextCreateImage(bitmapContext);

    // Release the bitmap context object and free the associated raster memory.

    CGContextRelease(bitmapContext);

    free(data);

    // Return the CGImage object this code created from the drawing.

    return image;

}

void myExportCGDrawingAsPNG(CFURLRef url, OSType drawingCommand)

{

    float dpi = 300;

    // Create an RGBA image from the Quartz drawing that corresponds to drawingCommand.

    CGImageRef image = createRGBAImageFromQuartzDrawing(dpi, drawingCommand);

    CFTypeRef keys[2], values[2]; 

    CFDictionaryRef properties = NULL;

    // Create a CGImageDestination object will write PNG data to URL.

    // We specify that this object will hold 1 image.

    CGImageDestinationRef imageDestination = 

    CGImageDestinationCreateWithURL(url, kUTTypePNG, 1, NULL);

    // Set the keys to be the x and y resolution properties of the image.

    keys[0] = kCGImagePropertyDPIWidth;

    keys[1] = kCGImagePropertyDPIHeight;

    // Create a CFNumber for the resolution and use it as the 

    // x and y resolution.

    values[0] = values[1] = CFNumberCreate(NULL, kCFNumberFloatType, &dpi);

    // Create an properties dictionary with these keys.

    properties = CFDictionaryCreate(NULL, 

                 (const void **)keys, 

                 (const void **)values, 

                 2,  

                 &kCFTypeDictionaryKeyCallBacks,

                 &kCFTypeDictionaryValueCallBacks); 

    // Release the CFNumber the code created.

    CFRelease(values[0]);

    // Add the image to the destination, characterizing the image with

    // the properties dictionary.

    CGImageDestinationAddImage(imageDestination, image, properties);

    // Release the CGImage object that createRGBAImageFromQuartzDrawing

    // created.

    CGImageRelease(image);

    // Release the properties dictionary.

    CFRelease(properties);

    // When all the images (only 1 in this example) are added to the destination, 

    // finalize the CGImageDestination object. 

    CGImageDestinationFinalize(imageDestination);

    // Release the CGImageDestination when finished with it.

    CFRelease(imageDestination);

}

static CGLayerRef createCachedContent(CGContextRef c){

    // The cached content will be 50x50 units.

    float width = 50, height = 50;

    CGLayerRef layer;

    // Create the layer to draw into.

    layer = CGLayerCreateWithContext(c,  CGSizeMake(width, height), NULL);

    // Get the CG context corresponding to the layer.

    CGContextRef layerContext = CGLayerGetContext(layer);

    // Cache some very simple drawing just as an example.

    CGContextFillRect(layerContext, CGRectMake(0, 0, width, height) );

    // The layer now contains cached drawing so return it.

    return layer;

}

static void drawSimpleCGLayer(CGContextRef context)

{

    // Create a CGLayer object that represents some drawing.

    CGLayerRef layer = createCachedContent(context);

    // Get the size of the layer created.

    CGSize s = CGLayerGetSize(layer); 

    // Position the drawing to an appropriate location.

    CGContextTranslateCTM(context, 40, 100);

    int i;

    // Paint 4 columns of layer objects.

    for(i = 0 ; i < 4 ; i++){

    // Draw the layer at the point that varies as the code loops.

    CGContextDrawLayerAtPoint(context, 

                CGPointMake(2*(i+1)*s.width, 0), 

                layer);

    }

    // Release the layer when finished drawing with it.

    CGLayerRelease(layer); 

}

// The equivalent drawing as doSimpleCGLayer but without creating

// a CGLayer object and caching that drawing to a layer.

static void drawUncachedForLayer(CGContextRef context)

{

    CGRect r = CGRectMake(0, 0, 50, 50); 

    CGContextTranslateCTM(context, 40, 100);

    int i;

    for(i = 0 ; i < 4 ; i++){ // Paint 4 columns of layer objects.

    // Adjust the origin as the code loops. Recall that

    // transformations are cummulative.

    CGContextTranslateCTM( context, 2*CGRectGetWidth(r), 0 );

    CGContextFillRect(context, r); // Do the uncached drawing.

    }

}

// Create a PDF document at 'url' from the drawing represented by drawingCommand. 

void myCreatePDFDocument(CFURLRef url, OSType drawingCommand) 

{

    // mediaRect represents the media box for the PDF document the code is

    // creating. The size here is that of a US Letter size sheet.

    const CGRect mediaRect = CGRectMake(0, 0, 8.5*72, 11*72);

    // Create a CGContext object to capture the drawing as a PDF document located

    // at 'url'.

    CGContextRef pdfContext = CGPDFContextCreateWithURL(url, &mediaRect, NULL);

    // Start capturing drawing on a page. 

    CGContextBeginPage(pdfContext, &mediaRect);

    // Perform drawing for the first page.

    myDispatchDrawing(pdfContext, drawingCommand);

    // Tell the PDF context that drawing for the current page is finished.

    CGContextEndPage(pdfContext);

    /* If there were more pages they would be captured as:

        CGContextBeginPage(pdfContext, &mediaRect);

    DrawingForPage2(pdfContext);

    CGContextEndPage(pdfContext);

    CGContextBeginPage(pdfContext, &mediaRect);

    ....

    */

    // When done with drawing to the PDF context, the code needs to release it.

    // Without releasing the context the contents of the PDF document will not be

    // flushed properly.

    CGContextRelease(pdfContext);  

}