Web-Drafter update: Color Picker

My very tiny vector graphics application is improving at a snail pace.

I managed to make a colour picker using jQuery and the HTML range input element.

The code isn’t exactly succinct, but it gets the job done.

Because the program is growing larger, I’m trying to use the OOP facets of JavaScript and put the functions in their respective objects as much as possible, the loose functions in the posfunc.js file creates the dialog:

function color_selector_form(color) {
    frgb = color.get_fill_rgb();
    srgb = color.get_stroke_rgb();

    var red_slider = "<input class='fill_slider' id='red_slider' value="+frgb[0]+" type=\"range\" min=\"0\" max=\"255\"> <br> <div id='rfval' >"+frgb[0]+"</div><br> ";
    var green_slider = "<input class='fill_slider' id='green_slider' value="+frgb[1]+" type=\"range\" min=\"0\" max=\"255\"> <br> <div id='gfval' >"+frgb[1]+"</div><br>";
    var blue_slider = "<input class='fill_slider' id='blue_slider' value="+frgb[2]+" type=\"range\" min=\"0\" max=\"255\"> <br> <div id='bfval' >"+frgb[2]+"</div><br>";
    var fcbox = "<span id=\"fillbox\" style=\"background-color: "+color.fill+"; display: block; height: 50px; width: 50px;\">&nbsp</span>";

    var red_stroke_slider = "<input class='stroke_slider' id='red_stroke_slider' value="+srgb[0]+" type=\"range\" min=\"0\" max=\"255\"> <br> <div id='rsval' >"+srgb[0]+"</div><br> ";
    var green_stroke_slider = "<input class='stroke_slider' id='green_stroke_slider' value="+srgb[1]+" type=\"range\" min=\"0\" max=\"255\"> <br> <div id='gsval' >"+srgb[1]+"</div><br>";
    var blue_stroke_slider = "<input class='stroke_slider' id='blue_stroke_slider' value="+srgb[2]+" type=\"range\" min=\"0\" max=\"255\"> <br> <div id='bsval' >"+srgb[2]+"</div><br>";
    var scbox = "<span id=\"strokebox\" style=\"background-color: "+color.stroke+"; display: block; height: 50px; width: 50px;\">&nbsp</span>";

    var retval = "<table><tr><td>Fill<br><br>";
    retval += "Red: <br>" + red_slider + "Green: <br>" + green_slider + "Blue: <br>" + blue_slider + "<br>" + fcbox;
    retval += "</td><td>&nbsp&nbsp&nbsp</td><td>Stroke<br><br>";
    retval += "Red: <br>" + red_stroke_slider + "Green: <br>" + green_stroke_slider + "Blue: <br>" + blue_stroke_slider + "<br>" + scbox;
    retval += "</td></tr></table>";
    return retval;
}

While the pos.js has the $(document).ready() functions for the dynamically created elements:

jQuery(document).on("change mousemove", ".fill_slider", function() {
   selected_color.update_fill(jQuery(this).val(), jQuery(this).attr("id"));
   var id = jQuery(this).attr("id");
   //console.log(id + " " +jQuery(this).val());
   if(id.substring(1, 2) == "r") {
        jQuery("#red_val").html(jQuery(this).val());
       } else  if(id.substring(1, 2) == "g") {
           jQuery("#green_val").html(jQuery(this).val());
       } else  if(id.substring(1, 2) == "b") {
           jQuery("#blue_val").html(jQuery(this).val());
       }
   });

Which in turn calls the appropriate methods in the MyColor object.

MyColor.prototype.update_fill = function(colorval, id) {
    var hexredval = parseInt(colorval).toString(16);
    if(hexredval.length < 2)
        hexredval = "0" + hexredval;
    var channel = id.substring(0,1);
    if(channel == "r")
        this.fill = (this.fill.substring(0, 1) + hexredval.substring(0, 2) + this.fill.substring(3)).toUpperCase();
    else if(channel == "g")
        this.fill = (this.fill.substring(0, 3) + hexredval.substring(0, 2) + this.fill.substring(5)).toUpperCase();
    else if(channel == "b")
        this.fill = (this.fill.substring(0, 5) + hexredval.substring(0, 2)).toUpperCase();
    jQuery("#" + channel + "fval").html(colorval);
    jQuery("#fillbox").css("background-color", this.fill);
    update_color(this);
}

As you can see, the code isn’t really DRY, but I find that making a clumsy solution is a great way to start a project and get anything done whatsoever, and then improve on it (or just keep it until it becomes cluttered).

Interactive jQuery Menu

A few days ago I was asked to update the layout of the website for a store I used to work at.

I thought this was a good chance to get to know jQuery animations, so I put together a bunch of stock images as background, edited pictures of frames and put some text in the frames for the icons.

I worked with artboards in Affinity Designer so I could export multiple images to different files, I also worked with groups and a transparent background so I could make .png files of the frames and put them on top of the background images.

That way I used the background-image css property, with display set to block and could superimpose a png with transparency over another image.

With jQuery I selected all images, where each image has a class “RT” and I used the reserved word this to select the particular instance for mouseover and mouseleave events.

With this I managed to make a fun little menu where the frame with the text grows and shrinks according to mouse-events.

The result can be seen here.

Regex 101

Today I received an email from the store I used to work at asking me to make a printer friendly version of an online table of information.

As I learned more about regular expressions from the “INF3331” course I took this fall, solving this problem proved to be way easier than any previous attempts at the likes of it.

At times I’ve thought that regexes are harder to read and debug than ordinary programming languages, but with a good editor like Atom or the regex101 page, it all became a lot less stressful.

As far as editors go, I have to admit that I still use emacs when I’m not using an IDE or GUI-editor.

Note to self about regular expressions.

(.*?) to capture zero or more characters in a non-greedy manner

(?:.*?) for the same grouping without backreferences.

$1 or $[group-number] for backreferences in JavaScript and Atom

\1 or \[group-number] for backreferences in Python, PHP.

Perl and PHP also uses \g1 or \g[group-number] for backreferences.

The following characters need to be escaped in regex:

.^$*+?()[{\|

Web Drafter

A tiny online vector graphics application.

Click here to try it out.

As a small project to familiarise myself with JavaScript, jQuery and SVG I started working on a small vector graphics app using the SVG.js library.

At first I was thinking of manipulating SVG-text directly as I had done with my desktop Java applications, but since I found that simply appending or updating the inner html of divs didn’t refresh the SVG canvas and other annoying things I found it was smarter to just use a simple JavaScript library for this.

In addition to learning a lot of jQuery and JavaScript, especially understanding the specifics of JavaScripts idiosyncratic approach to OOP, I learned a bit about which existing libraries there are and how to use them. For this small application, SVG.js did nicely, but I also learned about a larger library called Raphaël, and an interesting little script called Flowtype, that automagically resizes the font size in relation to the window size.

I put the source code of my little application on GitHub here.

Up to now I’ve only managed to do the most basic rectilinear polygons, with the foundations set for snapping and I’m planning to create a simple colour-picker functionality for the stroke, fill and opacity.

The hotkeys are:

cmd+z – UNDO (mac)

ctrl+z – UNDO (windows, linux)

D – Delete the last polygon.

S – Show data on the selected polygon.

Polygons are created by closing the path.

This is done by creating a line where the end coordinate is the same as the first coordinate of the polygon.

What week is this?

Today I was a bit impulsive and registered the domain name weeknum.org.

Then I made a little php-application showing the day of the week, with the background color calculated using the week number, month and day to create a hex code.

I might even try out some AJAX and jQuery on this page and see if I can make it a little more stylish and interactive.

If you want to check start and end dates of another week number, just add the suffix /[week number] to the URL.

For example, if you want to find information about week number 42, then go to weeknum.org/42.