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Java™ Binding for the OpenGL® API
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/**
* Copyright 2014 JogAmp Community. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification, are
* permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this list of
* conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice, this list
* of conditions and the following disclaimer in the documentation and/or other materials
* provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY JogAmp Community ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
* FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL JogAmp Community OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* The views and conclusions contained in the software and documentation are those of the
* authors and should not be interpreted as representing official policies, either expressed
* or implied, of JogAmp Community.
*/
package jogamp.nativewindow;
import com.jogamp.nativewindow.ScalableSurface;
/**
* Basic {@link ScalableSurface} utility to validate and compute pixel-scale values.
*/
public class SurfaceScaleUtils {
private static final float EPSILON = 1.1920929E-7f; // Float.MIN_VALUE == 1.4e-45f ; double EPSILON 2.220446049250313E-16d
private static boolean isZero(final float a) {
return Math.abs(a) < EPSILON;
}
/**
* Returns integer rounded product, i.e. {@code (int) ( a * pixelScale + 0.5f )}
*
* @param a the int value
* @param pixelScale the float scale factor
* @return the integer rounded product
*/
public static int scale(final int a, final float pixelScale) {
return (int) ( a * pixelScale + 0.5f );
}
/**
* Returns integer rounded product, i.e. {@code (int) ( a / pixelScale + 0.5f )}
*
* @param a the int value
* @param pixelScale the float scale factor
* @return the integer rounded product
*/
public static int scaleInv(final int a, final float pixelScale) {
return (int) ( a / pixelScale + 0.5f );
}
/**
* Returns integer rounded product, i.e. {@code (int) ( a * pixelScale + 0.5f )}
*
* @param result the int[2] result, may be {@code a} for in-place operation
* @param a the int[2] values
* @param pixelScale the float[2] scale factors
* @return the result for chaining
*/
public static int[] scale(final int[] result, final int[] a, final float[] pixelScale) {
result[0] = (int) ( a[0] * pixelScale[0] + 0.5f );
result[1] = (int) ( a[1] * pixelScale[1] + 0.5f );
return result;
}
/**
* Returns integer rounded product, i.e. {@code (int) ( a / pixelScale + 0.5f )}
*
* @param result the int[2] result, may be {@code a} for in-place operation
* @param a the int[2] values
* @param pixelScale the float[2] scale factors
* @return the result for chaining
*/
public static int[] scaleInv(final int[] result, final int[] a, final float[] pixelScale) {
result[0] = (int) ( a[0] / pixelScale[0] + 0.5f );
result[1] = (int) ( a[1] / pixelScale[1] + 0.5f );
return result;
}
/**
* Method constrains the given pixel-scale within ]0..{@code maxPixelScale}], as described below.
*
* Method returns {@link ScalableSurface#IDENTITY_PIXELSCALE IDENTITY_PIXELSCALE} if:
*
* - {@code pixelScale} ~= {@link ScalableSurface#IDENTITY_PIXELSCALE IDENTITY_PIXELSCALE}
*
*
*
* Method returns {@code maxPixelScale} if
*
* - {@code pixelScale} ~= {@link ScalableSurface#AUTOMAX_PIXELSCALE AUTOMAX_PIXELSCALE}
* - {@code pixelScale} > {@code maxPixelScale}
* - {@code pixelScale} ~= {@code maxPixelScale}
*
*
*
* Method returns {@code minPixelScale} if
*
* - {@code pixelScale} < {@code minPixelScale}
* - {@code pixelScale} ~= {@code minPixelScale}
*
*
*
* Otherwise method returns the given {@code pixelScale}.
*
*
* ~= denominates a delta ≤ {@link FloatUtil#EPSILON}.
*
* @param pixelScale pixel-scale to be constrained
* @param minPixelScale minimum pixel-scale
* @param maxPixelScale maximum pixel-scale
* @return the constrained pixel-scale
*/
public static float clampPixelScale(final float pixelScale, final float minPixelScale, final float maxPixelScale) {
if( isZero(pixelScale-ScalableSurface.IDENTITY_PIXELSCALE) ) {
return ScalableSurface.IDENTITY_PIXELSCALE;
} else if( isZero(pixelScale-ScalableSurface.AUTOMAX_PIXELSCALE) ||
pixelScale > maxPixelScale ||
isZero(pixelScale-maxPixelScale)
)
{
return maxPixelScale;
} else if( pixelScale < minPixelScale || isZero(pixelScale-minPixelScale) )
{
return minPixelScale;
} else {
return pixelScale;
}
}
/**
* Method {@link #clampPixelScale(float, float, float) constrains} the given float[2] pixel-scale
* within ]0..{@code maxPixelScale}], as described in {@link #clampPixelScale(float, float, float)}.
*
* @param result float[2] storage for result, maybe same as s for in-place
* @param pixelScale float[2] pixelScale to be constrained
* @param minPixelScale float[2] minimum pixel-scale
* @param maxPixelScale float[2] maximum pixel-scale
* @return the constrained result for chaining
*/
public static float[] clampPixelScale(final float[] result, final float[] pixelScale,
final float[] minPixelScale, final float[] maxPixelScale) {
result[0] = clampPixelScale(pixelScale[0], minPixelScale[0], maxPixelScale[0]);
result[1] = clampPixelScale(pixelScale[1], minPixelScale[1], maxPixelScale[1]);
return result;
}
/**
* Method writes the given float[2] requested pixel-scale {@code reqPixelScale}
* into {@code result} within its constraints ]0..{@code maxPixelScale}], as described in {@link #clampPixelScale(float, float, float)}.
*
* Method only differs from {@link #clampPixelScale(float[], float[], float[], float[])}
* by returning the whether the value has changed, i.e. different from the given {@code prePixelScale}.
*
*
* @param result int[2] storage for result, maybe same as prePixelScale for in-place
* @param prePixelScale float[2] previous pixel-scale
* @param reqPixelScale float[2] requested pixel-scale, validated via {@link #validateReqPixelScale(float[], float[], String)}.
* @param minPixelScale float[2] minimum pixel-scale
* @param maxPixelScale float[2] maximum pixel-scale
* @param DEBUG_PREFIX if set, dumps debug info on stderr using this prefix
* @param newPixelScaleRaw new raw surface pixel-scale
* @return {@code true} if pixel-scale has changed, otherwise {@code false}.
*/
public static boolean setNewPixelScale(final float[] result,
final float[] prePixelScale, final float[] reqPixelScale,
final float[] minPixelScale, final float[] maxPixelScale,
final String DEBUG_PREFIX) {
final float resultX = clampPixelScale(reqPixelScale[0], minPixelScale[0], maxPixelScale[0]);
final float resultY = clampPixelScale(reqPixelScale[1], minPixelScale[1], maxPixelScale[1]);
final boolean changed = resultX != prePixelScale[0] || resultY != prePixelScale[1];
if( null != DEBUG_PREFIX ) {
System.err.println(DEBUG_PREFIX+".setNewPixelScale: pre["+prePixelScale[0]+", "+prePixelScale[1]+"], req["+
reqPixelScale[0]+", "+reqPixelScale[1]+"], min["+
minPixelScale[0]+", "+minPixelScale[1]+"], max["+
maxPixelScale[0]+", "+maxPixelScale[1]+"] -> result["+
resultX+", "+resultY+"], changed "+changed);
}
result[0] = resultX;
result[1] = resultY;
return changed;
}
}