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package com.jogamp.graph.font;
/**
* Simple static font scale methods for unit conversion.
*/
public class FontScale {
/**
* Converts typical font size in points (per-inch) and screen resolution in dpi to font size in pixels (per-inch),
* which can be used for pixel-size font scaling operations.
* <p>
* Note that 1em == size of the selected font.<br/>
* In case the pixel per em size is required (advance etc),
* the resulting pixel-size (per-inch) of this method shall be used if rendering directly into the screen resolution!
* </p>
* <pre>
Font Scale Formula:
1 inch = 25.4 mm
1 inch = 72 points
pointSize: [point] = [1/72 inch]
[1] Scale := pointSize * resolution / ( 72 points per inch * units_per_em )
[2] PixelSize := pointSize * resolution / ( 72 points per inch )
[3] Scale := PixelSize / units_per_em
* </pre>
* @param font_sz_pt in points (per-inch)
* @param res_dpi display resolution in dots-per-inch
* @return pixel-per-inch, pixelSize scale factor for font operations.
* @see #toPixels2(float, float)
*/
public static float toPixels(final float font_sz_pt /* points per inch */, final float res_dpi /* dots per inch */) {
return ( font_sz_pt / 72f /* points per inch */ ) * res_dpi;
}
/**
* Converts typical font size in points-per-inch and screen resolution in points-per-mm to font size in pixels (per-inch),
* which can be used for pixel-size font scaling operations.
*
* @param font_sz_pt in points (per-inch)
* @param res_ppmm display resolution in dots-per-mm
* @return pixel-per-inch, pixelSize scale factor for font operations.
* @see #toPixels(float, float)
*/
public static float toPixels2(final float font_sz_pt /* points per inch */, final float res_ppmm /* pixels per mm */) {
return ( font_sz_pt / 72f /* points per inch */ ) * ( res_ppmm * 25.4f /* mm per inch */ ) ;
}
/**
* Converts [1/mm] to [1/inch] in place
* @param ppmm float[2] [1/mm] value
* @return return [1/inch] value
*/
public static float[/*2*/] perMMToPerInch(final float[/*2*/] ppmm) {
ppmm[0] *= 25.4f;
ppmm[1] *= 25.4f;
return ppmm;
}
/**
* Converts [1/mm] to [1/inch] into res storage
* @param ppmm float[2] [1/mm] value
* @param res the float[2] result storage
* @return return [1/inch] value, i.e. the given res storage
*/
public static float[/*2*/] ppmmToPPI(final float[/*2*/] ppmm, final float[/*2*/] res) {
res[0] = ppmm[0] * 25.4f;
res[1] = ppmm[1] * 25.4f;
return res;
}
}
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