1 files changed, 70 insertions, 0 deletions
diff --git a/src/jogl/classes/com/jogamp/graph/font/FontScale.java b/src/jogl/classes/com/jogamp/graph/font/FontScale.java
new file mode 100644
index 000000000..a0f2ef4e0
--- /dev/null
+++ b/src/jogl/classes/com/jogamp/graph/font/FontScale.java
@@ -0,0 +1,70 @@
+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;
+    }
+}