Leave That Thing Alone

ColdFusion Image Histogram

Example Output Color Histogram Image:

Example Output Histogram Image:

Example Source Image:

CFDump of color histogam and statistics:

This ColdFusion component creates black/white and color image histograms.

the component will return a structure containing histogram array(s) and statistics and/or will write PNG images of the histogram.

ColdFusion 8 Version:
Uses standard Java API currently available to ColdFusion 8, no need for external libraries (JAI now avaiable to CF8). ColdFusion 8 Version now returns an image (in cfimage format) of a B/W or color histogram.

ColdFusion 7 Version:
Uses standard Java API currently available to ColdFusion, no need for external libraries. New: JAI (Java Advanced Imaging) will be used if available in ColdFusion Class Path. Using JAI provides a massive speed increase.

Download

• CFImageHistogram (49Kbytes) - June 30, 2007
  imageHistogram Version 0.3.1 & CF8ImageHistogram 0.1

Example Uses

• Search images by color
• Download example presentation with search by color functionality

Features

• Can be used to index colors of images so they can be searched
• Creates Black/White and color histograms
• Returns histogram statistics: min, max, mean, standard deviation
• Creates B/W and color histogram images
• Can create histogram from JPG file and path or from a buffered image
• Can use JAI (if available in ColdFusion Class Path) or if JAI not available will standard Java API currently available to ColdFusion 6/7
• Massive speed increase in version 0.3 when using JAI
• Apache License, version 2

Known Issues:

• Output PNG width currently set to 256 pixels
• VERY slow if JAI not used
• Histogram image output accuracy not well tested
• Using JAI is highly recommended

 Feedback, bugs, feature request, better ideas are greatly appreciated.

ColdFusion 8 Histogram CFC Example Usage

• getHistogram - retuns a structure that contains a histogram array[256] and histogram statistics
• getColorHistogram - returns a structure that contains a color histogram array[3][256] and histogram statistics
• getHistogramImage - Returns an image histogram in cfimage format
• getColorHistogramImage - Returns a color image histogram in cfimage format
• setBufferedImage - allows you to define a buffered image to retrieve histogram from

Example use to get color histogram array from an image:
<cfset ih = createObject("component","imageHistogramCF8").init() />
<cfset image = expandPath("01.jpg") />
<cfset hist = ih.getColorHistogram(image) />
<cfdump var="#hist#">


Example of displaying a color histogram image:
<cfimage action="read" source="01.jpg" name="image" />
<cfset ih = createObject("component","imageHistogramCF8").init() />
<cfset hist = ih.getColorHistogramImage(image) />
<cfimage action="writeToBrowser" source="#hist#" />

ColdFusion 7 Histogram CFC Example Usage

• getHistogram - retuns a structure that contains a histogram array[256] and histogram statistics
• getHistogramImage - Creates an image (PNG) histogram
• getColorHistogram - retuns a structure that contains a color histogram array[3][256] and histogram statistics
• getColorHistogramImage - Creates an color image (PNG) histogram
• getHistogramValue - reutrn the value of the variables.histogram structure (will be empty unless one of the above functions is called first)
• setBufferedImage - allows you to define a buffered image to retrieve histogram from without having to specify a file path
• setImageBackgroundColor - sets the background color for the PNG images created red,green,blue,alpha

<cfscript>
//return histogram structure of supplied image
imageHistogram = createObject("component","imageHistogram").init();
histogram = imageHistogram.getHistogram(expandPath("test.jpg"));

//create histogram image
imageHistogram = createObject("component","imageHistogram").init();
imageHistogram.getHistogramImage(expandPath("test.jpg"),expandPath("hist.png"));

//return color histogram structure of supplied image
imageHistogram = createObject("component","imageHistogram").init();
histogram = imageHistogram.getColorHistogram(expandPath("test.jpg"));

//create color histogram image
imageHistogram = createObject("component","imageHistogram").init();
imageHistogram.getColorHistogramImage(expandPath("test.jpg"),expandPath("hist.png"));

//set white background PNG histogram image color
imageHistogram = createObject("component","imageHistogram").init();
imageHistogram.setImageBackgroundColor(255,255,255,255);

//get histogram from already buffered image, variable 'bufferedImage'
imageHistogram = createObject("component","imageHistogram").init();
imageHistogram.setBufferedImage(bufferedImage);
histogram = imageHistogram.getHistogram();
</cfscript>