From 2cc4789cf67fe8aab66f3e2ef787d571d0b3b4e5 Mon Sep 17 00:00:00 2001
From: Michael R Sweet <msweet@msweet.org>
Date: Sun, 18 Jul 2021 09:50:22 -0400
Subject: [PATCH] Fix image writing issues for pdfioFileCreateImageObjFromData
 (Issue #15)

---
 pdfio-content.c |  6 ++++--
 testpdfio.c     | 23 ++++++++++++++++-------
 2 files changed, 20 insertions(+), 9 deletions(-)

diff --git a/pdfio-content.c b/pdfio-content.c
index e7c5903..22095b5 100644
--- a/pdfio-content.c
+++ b/pdfio-content.c
@@ -1694,7 +1694,8 @@ pdfioFileCreateImageObjFromData(
     pdfioDictSetNumber(dict, "Width", width);
     pdfioDictSetNumber(dict, "Height", height);
     pdfioDictSetNumber(dict, "BitsPerComponent", 8);
-    pdfioDictSetBoolean(dict, "ImageMask", true);
+    pdfioDictSetName(dict, "ColorSpace", "DeviceGray");
+    pdfioDictSetName(dict, "Filter", "FlateDecode");
 
     if ((decode = pdfioDictCreate(pdf)) == NULL)
     {
@@ -1703,7 +1704,7 @@ pdfioFileCreateImageObjFromData(
     }
 
     pdfioDictSetNumber(decode, "BitsPerComponent", 8);
-    pdfioDictSetNumber(decode, "Colors", num_colors - 1);
+    pdfioDictSetNumber(decode, "Colors", 1);
     pdfioDictSetNumber(decode, "Columns", width);
     pdfioDictSetNumber(decode, "Predictor", _PDFIO_PREDICTOR_PNG_AUTO);
     pdfioDictSetDict(dict, "DecodeParms", decode);
@@ -1746,6 +1747,7 @@ pdfioFileCreateImageObjFromData(
   pdfioDictSetNumber(dict, "Width", width);
   pdfioDictSetNumber(dict, "Height", height);
   pdfioDictSetNumber(dict, "BitsPerComponent", 8);
+  pdfioDictSetName(dict, "Filter", "FlateDecode");
 
   if (color_data)
     pdfioDictSetArray(dict, "ColorSpace", color_data);
diff --git a/testpdfio.c b/testpdfio.c
index ba799b0..8f8b4e8 100644
--- a/testpdfio.c
+++ b/testpdfio.c
@@ -772,7 +772,10 @@ write_alpha_test(
 	      if (i > 2)
 	      {
 	        // Add alpha channel
-	        *bufptr++ = (unsigned char)((x + y) / 2);
+	        if (x < 112 || x >= 144 || y < 112 || y >= 144)
+		  *bufptr++ = (unsigned char)((x - 128) * (y - 128));
+		else
+		  *bufptr++ = 0;
 	      }
 	    }
 	  }
@@ -792,7 +795,10 @@ write_alpha_test(
 	      if (i > 2)
 	      {
 	        // Add alpha channel
-	        *bufptr++ = (unsigned char)((x + y) / 2);
+	        if (x < 112 || x >= 144 || y < 112 || y >= 144)
+		  *bufptr++ = (unsigned char)((x - 128) * (y - 128));
+		else
+		  *bufptr++ = 0;
 	      }
 	    }
 	  }
@@ -817,7 +823,10 @@ write_alpha_test(
 	      if (i > 2)
 	      {
 	        // Add alpha channel
-	        *bufptr++ = (unsigned char)((x + y) / 2);
+	        if (x < 112 || x >= 144 || y < 112 || y >= 144)
+		  *bufptr++ = (unsigned char)((x - 128) * (y - 128));
+		else
+		  *bufptr++ = 0;
 	      }
 	    }
 	  }
@@ -828,7 +837,7 @@ write_alpha_test(
     printf("pdfioFileCreateImageObjFromData(num_colors=%u, alpha=%s): ", (unsigned)num_colors, i > 2 ? "true" : "false");
     if ((images[i] = pdfioFileCreateImageObjFromData(pdf, buffer, 256, 256, num_colors, NULL, i > 2, false)) != NULL)
     {
-      puts("PASS");
+      printf("PASS (%u)\n", (unsigned)pdfioObjGetNumber(images[i]));
     }
     else
     {
@@ -877,9 +886,9 @@ write_alpha_test(
       "DeviceGray",
       "DeviceRGB",
       "DeviceCMYK",
-      "DeviceGray + Alpha",
-      "DeviceRGB + Alpha",
-      "DeviceCMYK + Alpha"
+      "DevGray + Alpha",
+      "DevRGB + Alpha",
+      "DevCMYK + Alpha"
     };
 
     snprintf(iname, sizeof(iname), "IM%d", i + 1);