From 4e85aff8dc79d680f9b507f30053a17d27bbca42 Mon Sep 17 00:00:00 2001
From: scuri <scuri>
Date: Sun, 17 Jan 2010 18:15:37 +0000
Subject: New: function  imImageSetAlpha.

---
 html/en/history.html   |  3 ++-
 include/im_image.h     |  8 +++++++-
 src/im.def             |  1 +
 src/im_image.cpp       | 35 ++++++++++++++++++++++++++++++++++-
 src/lua5/imlua_image.c | 12 +++++++++++-
 5 files changed, 55 insertions(+), 4 deletions(-)

diff --git a/html/en/history.html b/html/en/history.html
index 78399e5..8c7f892 100644
--- a/html/en/history.html
+++ b/html/en/history.html
@@ -18,6 +18,8 @@
 		imImageCopyPlane</strong>.</li>
 		<li><span style="color: #0000FF">New:</span> function <strong>
 		imProcessCompose</strong>.</li>
+		<li><span style="color: #0000FF">New:</span> function <strong>
+		imImageSetAlpha</strong>.</li>
 	<li dir="ltr">
 		<span style="color: #008000">Changed:</span> libTIFF updated to version 
 		3.9.2.</li>
@@ -35,7 +37,6 @@
 		<li dir="ltr"><span style="color: #008000"><span style="color: #ff0000">Fixed:</span><span
             style="color: #000000"> alpha support in image:<strong>CopyPlane</strong>() 
 		and in channel indexing in Lua.</span></span></li>
-		<li dir="ltr"></li>
 </ul>
 <h3 dir="ltr">
     <a href="http://sourceforge.net/projects/imtoolkit/files/3.5/">Version 3.5</a> (02/Oct/2009)</h3>
diff --git a/include/im_image.h b/include/im_image.h
index 28c5369..6a325c1 100644
--- a/include/im_image.h
+++ b/include/im_image.h
@@ -103,12 +103,18 @@ imImage* imImageCreateBased(const imImage* image, int width, int height, int col
  * \ingroup imgclass */
 void imImageDestroy(imImage* image);
 
-/** Adds an alpha channel plane.
+/** Adds an alpha channel plane and sets its value to 0 (transparent).
  *
  * \verbatim image:AddAlpha() [in Lua 5] \endverbatim
  * \ingroup imgclass */
 void imImageAddAlpha(imImage* image);
 
+/** Sets the alpha channel plane to a constant.
+ *
+ * \verbatim image:SetAlpha() [in Lua 5] \endverbatim
+ * \ingroup imgclass */
+void imImageSetAlpha(imImage* image, float alpha);
+
 /** Changes the buffer size. Reallocate internal buffers if the new size is larger than the original.
  *
  * \verbatim image:Reshape(width: number, height: number) [in Lua 5] \endverbatim
diff --git a/src/im.def b/src/im.def
index 6efacc4..9c448d5 100644
--- a/src/im.def
+++ b/src/im.def
@@ -121,6 +121,7 @@ EXPORTS
   imImageCopyPlane
   imImageCreateBased
   imImageAddAlpha
+  imImageSetAlpha
   imDibToHBitmap
   imDibLogicalPalette
   imDibCaptureScreen
diff --git a/src/im_image.cpp b/src/im_image.cpp
index 171d897..5f865f8 100644
--- a/src/im_image.cpp
+++ b/src/im_image.cpp
@@ -2,7 +2,7 @@
  * \brief Image Manipulation
  *
  * See Copyright Notice in im_lib.h
- * $Id: im_image.cpp,v 1.6 2010/01/15 17:21:47 scuri Exp $
+ * $Id: im_image.cpp,v 1.7 2010/01/17 18:18:12 scuri Exp $
  */
 
 #include <stdlib.h>
@@ -273,6 +273,39 @@ void imImageClear(imImage* image)
     memset(image->data[image->depth], 0, image->plane_size);
 }
 
+template <class T> 
+inline void iSet(T *map, T value, int count)
+{
+  for (int i = 0; i < count; i++)
+  {
+    *map++ = value;
+  }
+}
+  
+void imImageSetAlpha(imImage* image, float alpha)
+{
+  assert(image);
+
+  if (image->has_alpha)
+  {
+    switch(image->data_type)
+    {
+    case IM_BYTE:
+      memset(image->data[image->depth], (imbyte)alpha, image->plane_size);
+      break;                                                                                
+    case IM_USHORT:                                                                           
+      iSet((imushort*)image->data[image->depth], (imushort)alpha, image->plane_size);
+      break;                                                                                
+    case IM_INT:                                                                           
+      iSet((int*)image->data[image->depth], (int)alpha, image->plane_size);
+      break;                                                                                
+    case IM_FLOAT:                                                                           
+      iSet((float*)image->data[image->depth], (float)alpha, image->plane_size);
+      break;                                                                                
+    }
+  }
+}
+
 int imImageIsBitmap(const imImage* image)
 {
   assert(image);
diff --git a/src/lua5/imlua_image.c b/src/lua5/imlua_image.c
index 77cc499..9900e7d 100644
--- a/src/lua5/imlua_image.c
+++ b/src/lua5/imlua_image.c
@@ -2,7 +2,7 @@
  * \brief IM Lua 5 Binding
  *
  * See Copyright Notice in im_lib.h
- * $Id: imlua_image.c,v 1.8 2010/01/15 17:23:13 scuri Exp $
+ * $Id: imlua_image.c,v 1.9 2010/01/17 18:18:12 scuri Exp $
  */
 
 #include <string.h>
@@ -127,6 +127,15 @@ static int imluaImageAddAlpha (lua_State *L)
   return 0;
 }
 
+/*****************************************************************************\
+ image:SetAlpha()
+\*****************************************************************************/
+static int imluaImageSetAlpha (lua_State *L)
+{
+  imImageSetAlpha(imlua_checkimage(L, 1), (float)luaL_checknumber(L, 2));
+  return 0;
+}
+
 /*****************************************************************************\
  image:Reshape()
 \*****************************************************************************/
@@ -1016,6 +1025,7 @@ static const luaL_reg imimage_lib[] = {
 static const luaL_reg imimage_metalib[] = {
   {"Destroy", imluaImageDestroy},
   {"AddAlpha", imluaImageAddAlpha},
+  {"SetAlpha", imluaImageSetAlpha},
   {"Reshape", imluaImageReshape},
   {"Copy", imluaImageCopy},
   {"CopyData", imluaImageCopyData},
-- 
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