Generating Fallback Avatars Using CFImage And ColdFusion

ADD ./fonts /usr/share/fonts/truetype

component
	accessors = true
	output = false
	hint = "I generate simple, initials-based avatars."
	{

	// Define properties for dependency-injection.
	property scratchDisk;

	// ---
	// PUBLIC METHODS.
	// ---

	/**
	* I generate an initials-based avatar and return the image binary. The image is always
	* generated as a JPG in order to match what Gravatar uses.
	*/
	public binary function generateAvatar(
		required string initials,
		required numeric size
		) {

		var imageData = withTempDirectory(
			( tempDirectory ) => {

				var image = imageNew( "", size, size, "rgb", "212121" );
				image.setDrawingColor( "ffffff" );
				image.setAntialiasing( true );

				var fontProperties = {
					font: "Roboto Mono Regular",
					size: ( fix( size / 3 ) - 2 )
				};
				// Since we don't know what text is going to be passed into the function,
				// we need to "measure" the text that will be rendered to the image when
				// using the given text value and font properties. We can then use this
				// to center the text within the canvas size.
				var bounds = measureText( image, initials, fontProperties );
				// Center text horizontally.
				var x = ( ( size / 2 ) - ( bounds.width / 2 ) - bounds.xOffset );
				// Center text vertically.
				var y = ( ( size / 2 ) + ( bounds.height / 2 ) );

				image.drawText( initials, x, y, fontProperties );

				// Save the image object to disk (Virtual File System in this case, for
				// fast file I/O operations).
				var imagePath = ( tempDirectory & "/avatar.jpg" );
				image.write( imagePath, 0.80 );

				return( fileReadBinary( imagePath ) );

			}
		);

		return( imageData );

	}

	// ---
	// PRIVATE METHODS.
	// ---

	/**
	* I get the bounding box dimensions of the given text as it would appear written to
	* the given image.
	*/
	private struct function measureText(
		required any image,
		required string text,
		required struct fontProperties
		) {

		var awtContext = image.getBufferedImage()
			.getGraphics()
			.getFontRenderContext()
		;
		// CAUTION: When decoding a font definition, you can use either a space (" ") or
		// a dash ("-") delimiter. But, you cannot mix-and-match the two characters. As
		// such, if you have a Font name which has spaces in it (ex, "Roboto Mono"), you
		// MUST USE the dash delimiter in order to prevent Java from parsing the font name
		// as a multi-item list. In this case, note that I am using the "-" because I know
		// my font name doesn't contain a dash.
		var awtFont = createObject( "java", "java.awt.Font" )
			.decode( "#fontProperties.font#-#fontProperties.size#" )
		;
		var bounds = createObject( "java", "java.awt.font.TextLayout" )
			.init( text, awtFont, awtContext )
			.getBounds()
		;

		return({
			width: bounds.width,
			height: bounds.height,
			xOffset: bounds.x,
			yOffset: bounds.y
		});

	}


	/**
	* I execute the given callback, passing in a temporary directory that can be used for
	* transient file IO. The temporary directory is deleted after the callback has been
	* executed.
	*/
	private any function withTempDirectory( required function callback ) {

		var folderPath = ( scratchDisk & "/" & createUuid() );

		try {

			directoryCreate( folderPath );

			return( callback( folderPath ) );

		} finally {

			directoryDelete( folderPath, true );

		}

	}

}

<cfscript>

	// NOTE: I'm using RAM disk (Virtual File System) as the scratch disk for the image
	// operations so that I get fast I/O performance.
	generator = new AvatarGenerator()
		.setScratchDisk( "ram://" )
	;

	cfcontent(
		type = "image/jpeg",
		variable = generator.generateAvatar( "BN", 120 )
	);

</cfscript>