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Re: Multiple image preload construct?

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Ken wrote:

> On 27.08.2013 16:02, Thomas 'PointedEars' Lahn wrote:
>> That is awful code style for array iteration, in probably every language
>> of the C family.  Consider this instead:
> 
> Oh, this is not C,

ECMAScript implementations rather clearly belong to the C *family* of 
programming languages as opposed to, for example, Python.

> this is ECMAScript in the JavaScript flavor,

No, it is any ECMAScript implementation, depending on the runtime 
environment in which it is executed.  See also
<http://PointedEars.de/es-matrix> pp.

> a dynamic language. Nothing is compiled, everything is interpreted.

No, that is a common misconception.  Source code for ECMAScript 
implementations is either JIT-compiled to bytecode that is executed by a 
Virtual Machine, or it is compiled to platform-native machine code.  There 
is a tendency now to JIT-compile to platform-native machine code, as can be 
seen with Apple/WebKit JavaScriptCore SquirrelFish Extreme and Google V8 
JavaScript.

> If you understand how interpreting works you would know this doesn't
> really matter (and in this case the bottleneck is not the loop).

YMMD.

>> It makes more sense to append the object reference to the Array *after*
>> the object is prepared:
> 
> Doesn't matter at all in this case.

Yes, it does.

> The Image element is a valid reference before src is set and image loading
> is an asynchrounous operation in JavaScript.

Image loading is not even part of JavaScript (or ECMAScript), it is a DOM 
feature.  You must have been asleep for the last decade or so.

> If its reference is kept in an array, object or as a variable does not
> matter at all as long as it is referenced.
> 
> Look at Image element as parent of data, not part of it.

I am referring to how easy source code can be read and understood by a 
*person*.  It is harder to understand if it is written your way.  This 
matters of the target audience is a (one) beginner.
 
>> It is even questionable to have the Image instance references in an
>> Array, as then there is no random access to them, for example by name or
>> ID.
> 
> I think you are forgetting that you can use the URL to identify which
> image has loaded if you need to reference its index.

I think you do not understand how Arrays are working in ECMAScript, and what 
image preloading is used for in DOM scripting.  I also think you should 
refresh your knowledge on hash tables, which are likely used internally for 
property lookup (as opposed to linear array search).

>> In your code you declare 3 global properties that should be avoided by
>> using namespacing (for lack of a better word):
> 
> You are missing the point here. I am not providing a full working
> solution but an example. It's up to OP to modify and adopt to suit his
> needs.

Bad examples are *bad* examples.  You should post good examples, especially 
as followup to beginners.

-- 
PointedEars

Twitter: @PointedEars2
Please do not Cc: me. / Bitte keine Kopien per E-Mail.

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Multiple image preload construct? Tuxedo <tuxedo@mailinator.com> - 2013-08-27 16:32 +0200
  Re: Multiple image preload construct? Tuxedo <tuxedo@mailinator.com> - 2013-08-27 17:06 +0200
  Re: Multiple image preload construct? Danny <dann90038@gmail.com> - 2013-08-27 10:29 -0700
  Re: Multiple image preload construct? Ken <usenet-so@abdiassoftware.com> - 2013-08-27 13:32 -0500
    Re: Multiple image preload construct? Tuxedo <tuxedo@mailinator.com> - 2013-08-27 20:54 +0200
      Re: Multiple image preload construct? Ken <usenet-so@abdiassoftware.com> - 2013-08-27 18:19 -0500
        Re: Multiple image preload construct? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2013-08-28 01:37 +0200
          Re: Multiple image preload construct? Ken <usenet-so@abdiassoftware.com> - 2013-08-27 18:47 -0500
    Re: Multiple image preload construct? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2013-08-27 23:02 +0200
      Re: Multiple image preload construct? Cezary Tomczyk <cezary.tomczyk@gmail.com> - 2013-08-27 23:20 +0200
        Re: Multiple image preload construct? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2013-08-28 01:27 +0200
          Re: Multiple image preload construct? Cezary Tomczyk <cezary.tomczyk@gmail.com> - 2013-08-29 03:56 +0200
            Re: Multiple image preload construct? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2013-08-29 15:16 +0200
      Re: Multiple image preload construct? Ken <usenet-so@abdiassoftware.com> - 2013-08-27 18:43 -0500
        Re: Multiple image preload construct? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2013-08-28 02:08 +0200
          Re: Multiple image preload construct? Ken <usenet-so@abdiassoftware.com> - 2013-08-27 19:49 -0500
            Re: Multiple image preload construct? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2013-08-28 03:17 +0200
              Re: Multiple image preload construct? Ken <usenet-so@abdiassoftware.com> - 2013-08-27 20:35 -0500
                Re: Multiple image preload construct? Dr J R Stockton <reply1300@merlyn.demon.co.uk.invalid> - 2013-08-29 19:32 +0100
              Re: Multiple image preload construct? John Harris <niam@jghnorth.org.uk.invalid> - 2013-08-28 16:20 +0100
            Re: Multiple image preload construct? Andrew Poulos <ap_prog@hotmail.com> - 2013-08-28 11:21 +1000
              Re: Multiple image preload construct? Ken <usenet-so@abdiassoftware.com> - 2013-08-27 20:48 -0500
                Re: Multiple image preload construct? Andrew Poulos <ap_prog@hotmail.com> - 2013-08-28 13:43 +1000
                Re: Multiple image preload construct? John Harris <niam@jghnorth.org.uk.invalid> - 2013-08-29 10:00 +0100
                Re: Multiple image preload construct? Andrew Poulos <ap_prog@hotmail.com> - 2013-08-30 07:25 +1000
                Re: Multiple image preload construct? John Harris <niam@jghnorth.org.uk.invalid> - 2013-08-30 10:11 +0100
        Re: Multiple image preload construct? Christoph Michael Becker <cmbecker69@arcor.de> - 2013-08-28 02:17 +0200
          Re: Multiple image preload construct? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2013-08-28 02:38 +0200
      Re: Multiple image preload construct? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2013-08-28 11:04 +0200
      Re: Multiple image preload construct? John Harris <niam@jghnorth.org.uk.invalid> - 2013-08-28 16:26 +0100

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