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HTML Color Selector
6/17/13
The other day I was playing around with my old canvas drawing class and thought to myself, I really could add more colors to this thing. Quickly using some loops to generate a number of color tabs I realized with only a little more effort I could make a full-on color selector class. So I did.
The algorithm isn't perfect but it does contain an extensive array of colors. You can pass two parameters to the class when instantiating. The fist (threshold) determines how many steps in color value the color selector will take between drawing color tiles. For example a threshold of 8, getting lighter, would build color tiles like so ((239,156,16), (247,164,24), (255,172,32)). The second parameter sets the square pixel size of the color tiles. If you don't set these they default to 8 and 2 respectively.
Here is an example of using this class...
... and this is how it's built on this very page.
In the second code snippet you see I'm doing a couple of things with the class before I call the init method. There are a number of public methods and event listeners you can use to interface with the CMDColorSelector.
* init : build the color selector to the document/parent
* select_color : returns the last color clicked on by user
* active_color : returns the value of the color the mouse last hovered over
* threshold : returns the threshold step value. threshold must be set on instantiation
* tab_size : retuns the sqare pixel size of the color tabs. tab_size must be set on instantiation
* inititalized : boolean, true if init() has been called
* parent : allows you to set the parent element the CMDColorSelector will be built on.
also can be used to get the current parent if no parameter is passed in.
you cannot set the parent if initialized is true
* RGBtoHEX : converst an rgb(0,0,0) based string to a hexidecimal based string
* setEvent : allows for stored functions to be called during certain class events.
The first param is the event type and the second is the function to be called (see EVENTS)
EVENTS
* onInit : executes at the end of the init() method
* onUpdateSC : executes whenever the selected_color value changes
* onUpdateAC : executes whenever the active_color value changes
Along the way I leaned two interesting things. First, IE (save for v8) has no support for the standard getter and setter methods that other browsers use, and the amount of code it takes to fix that issue just does not seem worth the effort and processing power. Second, in most versions of IE and Safari, mouse event bubbling (or registering) might not happen properly for child elements when their parent has a CSS display value of "block". To get around the second issue I set the parent elements CSS pointer-events value to none, while setting all of the clickable child elements pointer-events value to all.
In the (hopefully near) future I will be adding this color selector to the canvas drawing class. Who knows, with a couple more features I could have an on-line version of MS-Paint!