REPORT-103847 导出后蓝色图片不显示

fine-itext-old/src/main/java/com/fr/third/com/lowagie/text/Image.java

@@ -757,8 +757,25 @@ public abstract class Image extends Rectangle {
 								transparency[0] = transparency[1] = (transparentPixel >> 16) & 0xff;
 								transparency[2] = transparency[3] = (transparentPixel >> 8) & 0xff;
 								transparency[4] = transparency[5] = transparentPixel & 0xff;
+								// Added by Michael Klink
+								// Check whether this value for transparent pixels
+								// has already been used for a non-transparent one
+								// before this position
+								for (int prevPixel = 0; prevPixel < j; prevPixel++) {
+									if ((pixels[prevPixel] & 0xffffff) == transparentPixel) {
+										// found a prior use of the transparentPixel color
+										// and, therefore, cannot make use of this color
+										// for transparency; we could still use an image
+										// mask but for simplicity let's use a soft mask
+										// which already is implemented here
+										shades = true;
+										break;
+									}
+								}
 							}
-						} else if ((pixels[j] & 0xffffff) != transparentPixel) {
+						} else if (((pixels[j] & 0xffffff) != transparentPixel) && (alpha == 0)) {
+							shades = true;
+						} else if (((pixels[j] & 0xffffff) == transparentPixel) && (alpha != 0)) {
 							shades = true;
 						}
 					}