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## Usage

### Purpose

The purpose of this template is to allow accurate placement of an image and/or text label over another source image, irrespective of scaling of the source image. It is based on the {{Image label}} template. However, a drawback with that template is that the placement gets slightly inaccurate if you scale the source image (because of the way calculations are done), and thus you might have to manually recalculate the placement.

This template also has similarities with the {{Overlay}} template. That template however sadly doesn't allow for scaling. It is also limited to 30 labels, although for most purposes that is probably more than enough.

This template is however much more bloated than either of those templates, and you might want to consider if you can use one of the templates that are simpler and easier to use.

### Example usage

This template assumes you first introduce a background image by calling {{Image label begin}}. By doing so this also requires it to be ended with {{Image label end}}. Example with two smilies 15px placed as the “eyes” on this beach image.

{{Image label begin | image=Beach Smile.jpg | width=250 | float=right | title=Example }}
{{Image label marker | x=1079 | y=1033 | image=Face-grin.svg | marker_size=15 | width=250 | x_orig=2749 }}
{{Image label marker | x=1601 | y=1020 | image=Face-grin.svg | marker_size=15 | width=250 | x_orig=2749 }}
{{Image label end}}

For full list of available options/parameters see further below. In this example the following are used

• width = 250 is the width of the scaled image. This should correspond to the width you supplied when using {{Image label begin}}.
• x_orig = 2749 is in this example the width of the original beach image, which can be found out through various methods. One way to find out is the way Wikipedia/Commons lists it below the image where it says “Full resolution” when you view the image information and its license.
• x = 1079 is the x-coordinate on the full resolution image where the 15px is to be placed. There are various methods to find out this, and depends on what tools you have available.
• y = 1033 is the y-coordinate on the full resolution image where the 15px is to be placed.
• image = Face-grin.svg is the image to be used as a marker, since the default marker image 9px is not used.
• marker_size = 15 is the width of the marker image 15px.

If scaling the beach image down (or up), the only changes that need to be done is changing every occurrence of the width parameter, and the placement of overlying marker images (and their corresponding text) should scale accordingly.

{{Image label begin | image=Beach Smile.jpg | width=150 | float=right | title=Example }}
{{Image label marker | x=1079 | y=1033 | image=Face-grin.svg | marker_size=15 | width=150 | x_orig=2749 }}
{{Image label marker | x=1601 | y=1020 | image=Face-grin.svg | marker_size=15 | width=150 | x_orig=2749 }}
{{Image label end}}

### Minimal use skeleton

{{Image label marker
| x_marker_orig =
| y_marker_orig =
| x_scaled      =
| x_orig        =
| text          =
}}

If you want to use a different marker/image than the default Red pog.svg 7px, you can add it with

  | image         =
| marker_size   =

### Full skeleton

{{Image label marker
| x_marker_orig =
| y_marker_orig =
| x_scaled      =
| y_scaled      =
| x_orig        =
| y_orig        =
| text          =
| image         =
| marker_size   =
| show_image    =
| text_color    =
| text_align    =
| text_width    =
| font_size     =
| style         =
}}

Please note that many of these parameters are used in calculations. Due to constraints the template will think a parameter that is given, but is actually empty or contains spaces, still has a value and thus will give an error during calculations. The error might look something like this: Error en la expresión: falta un operando para +..

## Calculations

 yorig yscaled 250px 10px xmarker_origymarker_orig xorig xscaled

Default calculations used for placing the marker image. With the use of the template's parameter options xadjust and yadjust the placement can be slightly modified.

$x_{marker} = {x_{marker\_orig} \over x_{orig}} \cdot x_{scaled} - {marker\_size \over 2} + x_{adjust}$

and

$y_{marker} = {y_{marker\_orig} \over y_{orig}} \cdot y_{scaled} - {marker\_size \over 2} + y_{adjust}$

Where yscaled by default is calculated from the percentage the image is resized

$y_{scaled} = {x_{scaled} \over x_{orig}} \cdot y_{orig}$

Default calculations for the text placement, more specifically the upper left corner of the text's bounding box. The calculation inherits xadjust and yadjust from the marker image's placement. With the use of the template's parameter options xtextadjust and ytextadjust the text placement can be additionally modified.

$x_{text} = {x_{marker\_orig} \over x_{orig}} \cdot x_{scaled} + {marker\_size \over 2} + x_{adjust} + x_{textadjust}$

and

$y_{text} = {y_{marker\_orig} \over y_{orig}} \cdot y_{scaled} - {marker\_size \over 2} + y_{adjust} + y_{textadjust}$

## Template parameters

None of the template parameters are technically required, however not supplying a few of them will make the template behave oddly, or make the use of this template unnecessary. For this reason some of the parameters are listed as "required".

Parameter name Alternate names Required Description Recommended values
x_marker_orig x
x-marker-orig
yes The horizontal x-location on the original image where you want the centre of the marker to be located. 1 … xorig
y_marker_orig y
y-marker-orig
yes The vertical y-location on the original image where you want the centre of the marker to be located. 1 … yorig
x_scaled scale
width
x-scaled
yes The width of the resized image in pixels. Default is scaling it down (or up) to 250 pixels. 1 … xorig
y_scaled height
y-scaled
no The calculated height of the resized image in pixels. Note that the actual image height is implicitly set with {{Image label begin}}. Thus yscaled is mainly used internally, and by default it is calculated based on xscaled. If you do use this parameter, then you should also fill in a value for yorig or the calculations will end up wrong. 1 … yorig
x_orig width_orig
x-orig
width-orig
yes The width of the original image in pixels. If this value isn't corresponding with the original image's actual width, the calculations may be faulty. 1 … ?
y_orig height_orig
y-orig
height-orig
no The height of the original image in pixels. If this value isn't corresponding with the original image's actual height, the calculations may be faulty. You need to fill in a value for this parameter if you already used the yscaled parameter option, otherwise the calculations will end up wrong. 1 … ?
text no The text accompanying the marker image and shown close to the calculated (x, y) position. Default is no text. Any text
image no The image placed at the calculated (x, y) position. Default is Red pog.svg 7px. Any image
marker_size marker-size no The size (height and width) of the marker image that is placed. Default is 7 pixels wide. If the size is set to 0, then no image will be shown. It is assumed the shown marker image is a square so the height is equal to its width. If it is not a square you can modify the placement with the xadjust and/or yadjust options. 0 … ?
x_adjust x-adjust no A number of pixels you want the marker image to be moved horizontally after the initial scaling calculation has been done. Use for example if after calculation a rounding error moves the marker image a bit off from its wanted position. Default is 0. -xscaled+xscaled
y_adjust y-adjust no A number of pixels you want the marker image to be moved vertically after the initial scaling calculation has been done. Use for example if the marker image is not a square, or if after calculation a rounding error moves the marker image a bit off from its wanted position. Default is 0. -yscaled+yscaled
x_textadjust x-textadjust no A number of pixels you want the text's upper left corner to be moved horizontally after the initial scaling calculation has been done. Use for example if after calculation a rounding error or the font size moves the text's upper left corner a bit off from its wanted position. If a marker image was shown the default value is 3 pixels to give a little room between the image and the text. Otherwise the default is 0. -xscaled+xscaled
y_textadjust y-textadjust no A number of pixels you want the text's upper left corner to be moved vertically after the initial scaling calculation has been done. Use for example if after calculation a rounding error or the font size moves the text's upper left corner a bit off from its wanted position. Default is 0. -yscaled+yscaled
show_image showimage
show-image
no If this parameter contains anything else than its default value yes then the marker image will not be shown. Another way to do the same is to set the marker_size to 0. Any text or value
text_color color
text-color
no CSS-option specifying the color of the text accompanying the marker image. This value follows the valid options for specifying a web color with CSS. Default is black. predefined color name or

#000000#FFFFFF or
rgb(red, green, blue)

text_align text-align no CSS-option specifying the alignment of the accompanying marker text. Default value is left. left, right, center, justify
text_width text-width no CSS-option specifying the column width of the text accompanying the marker image. By default this is not set and follows the browser's calculations. Note that you need to add the units px or % etc., or otherwise the CSS the template generates will be incorrect. auto, 1px+xscaledpx, 1% … 100%
font_size font-size no CSS-option specifying the font size of the text accompanying the marker image. This value follows the valid options for specifying a font size with CSS. Predefined relative font sizes are xx-small, x-small, small, medium, large, x-large, xx-large, or it can be specified with a number in points pt, pixels px, ems em, percent %, cm, etc. By default this is not set and follows the text, font and style around the image. F.ex. 10pt, 20px, 1.5em, 125%, …
style no Any other CSS you want applied to the text. You need to write this out in full and as valid CSS. This will be applied to the whole text's (rectangle) bounding box, so if you want some CSS applied to only parts of the text you should not use this option, but instead use

<span style="some valid CSS;">some text</span>
on the specific parts of the text itself.

Any valid CSS