Aspect Switcher in ImageCache Actions 8
Same filename and directory in other branches
Using aspect switcher to create a 'square' setting.
This is done through "chaining" two switches - "is it quite wide or not?", then "is it quite tall or not?" which leaves us with "must be square then."
First we create the three sizes we will be using, small-landscape, small-square, small-portrait. I'll just set those up with scale_and_crop.
We want wide images up to a ratio of 1:0.75 to be rendered wide. We want squarish images, with an aspect between 1:0.75 and 1:1.25 to be rendered square, and anything taller to be rendered tall.
To do this, we chain 2 rules. We need to build them backwards, the smaller sub-rule first, but to understand, I'l list them top down.
Rule 1. is the master rule, 3-aspects
if ratio is less than 1:.75, use small-landscape. If greater, proceed to rule 2.
Rule 2. square-or-portrait
if ratio is less than 1:1.25, use small-square. If greater, use small-portrait.
To do this, we use the aspect switcher to link to the two sizes, and the ratio adjustment to move the switching point a little. Set the ratio adjustment to 1.25
With these (5!) rules in place, you can get the desired effect. This is a little trickier than just making a 'square' setting, but it allows for the required fudge factor to handle almost-square images.
You can nudge the adjustment factor to be looser or tighter. You can create even more chained rules, and define a 'super-wide' size.
| small-landscape | [Scale And Crop] width: 200, height: 100 |
| small-portrait | [Scale And Crop] width: 100, height: 200 |
| small-square | [Scale And Crop] width: 140, height: 140 |
| small-square-or-portrait | [Aspect Switcher] Portrait size: small-portrait. Landscape size: small-square (switch at 1:1.25) |
| small-3-aspects | [Aspect Switcher] Portrait size: small-square-or-portrait. Landscape size: small-landscape (switch at 1:.75) |
The illustration shows the result of this set-up on a collection of images. The listed dimensions are those of the source images. You'll see that the mostly-square ones are rendered square.
The rule being applied is: 1 Is it wide?
For image 250x300, the aspect is ( 250/300 = 0.83 ) Normally that number (less than 1) would be classified as 'portrait', and with the adjustment (*0.75) that is still true, so the processing passes through to the portrait preset.
rule #2 it it tall?
This preset however does a different set of maths, and multiplies the aspect by 1.25, producing a result that causes it to trigger to 'landscape' choice. 'landscape' at this point is set to be the 'square' preset. And we get what we wanted.
File
help/aspect_switcher.htmlView source
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>
Aspect Switcher
</title>
</head>
<body>
<h3>
Using aspect switcher to create a 'square' setting.
</h3>
<p>
This is done through "chaining" two switches - "is it quite
wide or not?", then "is it quite tall or not?" which leaves
us with "must be square then."
</p>
<p>
First we create the three sizes we will be using,
small-landscape, small-square, small-portrait. I'll just set
those up with scale_and_crop.
</p>
<p>
We want wide images up to a ratio of 1:0.75 to be rendered
wide. We want squarish images, with an aspect between 1:0.75
and 1:1.25 to be rendered square, and anything taller to be
rendered tall.
</p>
<p>
To do this, we chain 2 rules. We need to build them
backwards, the smaller sub-rule first, but to understand, I'l
list them top down.
</p>
<p>
Rule 1. is the master rule, <strong>3-aspects</strong>
</p>
<p>
if ratio is less than 1:.75, use small-landscape. If greater,
<strong>proceed to rule 2</strong>.
</p>
<p>
</p>
<p>
Rule 2. <strong>square-or-portrait</strong>
</p>
<p>
if ratio is less than 1:1.25, use small-square. If greater,
use small-portrait.
</p>
<p>
To do this, we use the aspect switcher to link to the two
sizes, and the <em>ratio adjustment</em> to move
the switching point a little. Set the ratio adjustment to
1.25
</p>
<p>
With these (5!) rules in place, you can get the desired
effect. This is a little trickier than just making a 'square'
setting, but it allows for the required fudge factor to
handle almost-square images.
</p>
<p>
You can nudge the adjustment factor to be looser or tighter.
You can create even more chained rules, and define a
'super-wide' size.
</p>
<table border="1" cellpadding="1" cellspacing="1">
<tbody>
<tr>
<td rowspan="1" colspan="1">
small-landscape
</td>
<td rowspan="1" colspan="1">
[Scale And Crop] width: 200, height: 100
</td>
</tr>
<tr>
<td rowspan="1" colspan="1">
small-portrait
</td>
<td rowspan="1" colspan="1">
[Scale And Crop] width: 100, height: 200
</td>
</tr>
<tr>
<td rowspan="1" colspan="1">
small-square
</td>
<td rowspan="1" colspan="1">
[Scale And Crop] width: 140, height: 140
</td>
</tr>
<tr>
<td rowspan="1" colspan="1">
small-square-or-portrait
</td>
<td rowspan="1" colspan="1">
[Aspect Switcher] Portrait
size: <strong>small-portrait</strong>. Landscape
size: <strong>small-square</strong> (switch
at 1:1.25)
</td>
</tr>
<tr>
<td rowspan="1" colspan="1">
small-3-aspects
</td>
<td rowspan="1" colspan="1">
[Aspect Switcher] Portrait
size: <strong>small-square-or-portrait</strong>.
Landscape
size: <strong>small-landscape</strong> (switch
at 1:.75)
</td>
</tr>
</tbody>
</table>
<p>
The illustration shows the result of this set-up on a
collection of images. The listed dimensions are those of the
source images. You'll see that the mostly-square ones are
rendered square.
</p>
<img src="../docs/aspect-chaining.png" alt="Illustration of several different sized images passing through the above ruleset."/>
<p>
The rule being applied is: 1 Is it wide?
</p>
<p>
For image 250x300, the aspect is ( 250/300 = 0.83 ) Normally
that number (less than 1) would be classified as 'portrait',
and with the adjustment (*0.75) that is still true, so the
processing passes through to the portrait preset.
</p>
<p>
rule #2 it it tall?
</p>
<p>
This preset however does a different set of maths, and
multiplies the aspect by 1.25, producing a result that causes
it to trigger to 'landscape' choice. 'landscape' at this
point is set to be the 'square' preset. And we get what we
wanted.
</p>
</body>
</html>