Add DeviceRGB constructor that takes system's color

DEVSIX-1358

Author: IdamkinI

io/src/main/java/com/itextpdf/io/LogMessageConstant.java

@@ -53,6 +53,7 @@ public final class LogMessageConstant {
     public static final String ATTEMPT_TO_MOVE_TO_FLUSHED_PARENT = "An attempt is made to move the tag tree pointer to the tag parent which has been already flushed. Tag tree pointer is moved to the root tag instead.";
     public static final String CALCULATE_HASHCODE_FOR_MODIFIED_PDFNUMBER = "Calculate hashcode for modified PdfNumber.";
     public static final String CLIP_ELEMENT = "Element content was clipped because some height properties are set.";
+    public static final String COLOR_ALPHA_CHANNEL_IS_IGNORED = "Alpha channel {0} was ignored during creation of color";
     public static final String COLORANT_INTENSITIES_INVALID = "Some of colorant intensities are invalid: they are bigger than 1 or less than 0. We will force them to become 1 or 0 respectively.";
     public static final String COLOR_NOT_FOUND = "Color \"{0}\" not found.";
     public static final String COLOR_NOT_PARSED = "Color \"{0}\" was not parsed. It has invalid value. Defaulting to black color.";

kernel/src/main/java/com/itextpdf/kernel/color/DeviceRgb.java

@@ -44,6 +44,7 @@ This file is part of the iText (R) project.
 package com.itextpdf.kernel.color;
 
 import com.itextpdf.io.LogMessageConstant;
+import com.itextpdf.io.util.MessageFormatUtil;
 import com.itextpdf.kernel.pdf.colorspace.PdfDeviceCs;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -115,6 +116,20 @@ public DeviceRgb(float r, float g, float b) {
         }
     }
 
+    /**
+     * Create DeviceRGB color from R, G, B values of java.awt.Color
+     * Note, that alpha chanel is ignored
+     *
+     * @param color the color which RGB values are used
+     */
+    public DeviceRgb(java.awt.Color color) {
+        this(color.getRed(), color.getGreen(), color.getBlue());
+        if (color.getAlpha() != 255) {
+            Logger LOGGER = LoggerFactory.getLogger(DeviceRgb.class);
+            LOGGER.warn(MessageFormatUtil.format(LogMessageConstant.COLOR_ALPHA_CHANNEL_IS_IGNORED, color.getAlpha()));
+        }
+    }
+
     /**
      * Creates DeviceRgb color with all colorants intensities initialised as zeroes.
      */