Cross Reference: /openjdk7/jdk/src/share/classes/java/awt/AlphaComposite.java

Lines Matching defs:alpha
32  * The <code>AlphaComposite</code> class implements basic alpha
47  * an alpha value that is used to modify the opacity or coverage of
53  * that are premultiplied by their corresponding alpha components.
63  * for combining color and alpha values in a purely mathematical
77  * <tr><td><em>A<sub>s</sub></em><td>the alpha component of the source pixel
79  * <tr><td><em>A<sub>d</sub></em><td>the alpha component of the destination pixel
84  * <tr><td><em>A<sub>r</sub></em><td>the alpha component of the result
119  * <tr><td><em>A<sub>ac</sub></em>  <td>the "extra" alpha component from the AlphaComposite instance
120  * <tr><td><em>A<sub>sr</sub></em> <td>the raw alpha component of the source pixel
121  * <tr><td><em>A<sub>dr</sub></em><td>the raw alpha component of the destination pixel
122  * <tr><td><em>A<sub>df</sub></em> <td>the final alpha component stored in the destination
130  * The <code>AlphaComposite</code> class defines an additional alpha
131  * value that is applied to the source alpha.
134  * alpha by multiplying both the raw source alpha and the raw
135  * source colors by the alpha in the <code>AlphaComposite</code>.
136  * This leads to the following equation for producing the alpha
143  * by the alpha in the <code>AlphaComposite</code> instance.
146  * source alpha.
155  * No adjustment needs to be made to the destination alpha:
190  * Note that since the division is undefined if the resulting alpha
214  * in the <code>BufferedImage</code> class, do not store alpha values
215  * for their pixels.  Such sources supply an alpha of 1.0 for
220  * Many destinations also have no place to store the alpha values
223  * alpha values that this class produces.
226  * values by the resulting alpha value before storing the color
227  * values and discarding the alpha value.
234  * and alpha component is at least adequate for use as a destination
275  * alpha values that uses 8 bits per component for storage.
286  * mode with no extra alpha, then the math would
296  * that is not premultiplied, dividing out the alpha will give us
338  * differently when encountering result alpha values of 0.0
340  * Note that the simplification of removing the divide by alpha
342  * denominator (alpha) is 0.
344  * when viewed in premultiplied form, a resulting alpha of 0
354      * Both the color and the alpha of the destination are cleared
520      * with an alpha of 1.0f.
527      * with an alpha of 1.0f.
534      * with an alpha of 1.0f.
542      * with an alpha of 1.0f.
549      * with an alpha of 1.0f.
556      * with an alpha of 1.0f.
563      * with an alpha of 1.0f.
570      * with an alpha of 1.0f.
577      * with an alpha of 1.0f.
584      * with an alpha of 1.0f.
592      * with an alpha of 1.0f.
600      * with an alpha of 1.0f.
616     private AlphaComposite(int rule, float alpha) {
620         if (alpha >= 0.0f && alpha <= 1.0f) {
622             this.extraAlpha = alpha;
624             throw new IllegalArgumentException("alpha value out of range");
670      * the constant alpha to multiply with the alpha of the source.
671      * The source is multiplied with the specified alpha before being composited
674      * @param alpha the constant alpha to be multiplied with the alpha of
675      * the source. <code>alpha</code> must be a floating point number in the
678      *         <code>alpha</code> is less than 0.0 or greater than 1.0, or if
685     public static AlphaComposite getInstance(int rule, float alpha) {
686         if (alpha == 1.0f) {
689         return new AlphaComposite(rule, alpha);
708      * Returns the alpha value of this <code>AlphaComposite</code>.  If this
709      * <code>AlphaComposite</code> does not have an alpha value, 1.0 is returned.
710      * @return the alpha value of this <code>AlphaComposite</code>.
748      * the specified alpha value.
749      * If this object already has the specified alpha value,
752      * this object that uses the specified alpha value.
753      * @param alpha the constant alpha to be multiplied with the alpha of
754      * the source. <code>alpha</code> must be a floating point number in the
757      *         <code>alpha</code> is less than 0.0 or greater than 1.0
760     public AlphaComposite derive(float alpha) {
761         return (this.extraAlpha == alpha)
763             : getInstance(this.rule, alpha);
781      * compositing rule and alpha value as this object.