Scaling a sprite means modifying that sprite's size by some multiple of its original size. For example, if we scale a 16 x 16 sprite by a scaling value of 2.0, the sprite will render to the canvas as a 32 x 32 image. This new container starts with four input elements, as well as their labels, which tell the particle system how to scale the particles over their lifetimes. The min_starting_scale and max_starting_scale elements are the starting range scale of the particles. If you want the particle to always start with a scale of 1.0 (1 to 1 scale with the .png image size), you should put 1.0 in both of these fields. The actual starting scale value will be a randomly chosen value that falls between the two values you put in those fields. We haven't added any checks in this interface to verify that max is larger than min, so make sure that max is the same value or larger than the min value or this will break the emitter. The next two input elements are min_end_scale and max_end_scale. Like the starting scale values, the actual ending scale will be a randomly chosen value that falls between the two values we put in these fields. At any given point in a particle's lifetime, it will have a scale that is a value interpolated between the scale value assigned to the start of that particle's lifetime and the scale value at the end. So, if I start with a scale value of 1.0 and end with a scale value of 3.0, when the lifetime of the particle is half over, the scale value of the particle will be 2.0.
Here is what those elements look like in the HTML file:
<span class="label">min start scale:</span>
<input type="number" id="min_starting_scale" max="9.9" min="0.1" step="0.1" value="1.0" class="em_input"><br/>
<span class="label">max start scale:</span>
<input type="number" id="max_starting_scale" max="10.0" min="0.2" step="0.1" value="2.0" class="em_input"><br/>
<span class="label">min end scale:</span>
<input type="number" id="min_end_scale" max="9.9" min="0.1" step="0.1" value="1.0" class="em_input">
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<span class="label">max end scale:</span>
<input type="number" id="max_end_scale" max="10.0" min="0.2" step="0.1" value="2.0" class="em_input">
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