X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/8f49300284e2c91095ae3ebe62cb3a6d424eac21..f1df09276caf8575eed4e9bf2689c69903a749a9:/src/common/imagpcx.cpp

diff --git a/src/common/imagpcx.cpp b/src/common/imagpcx.cpp
index c78ac2f0b1..e6f2f05a87 100644
--- a/src/common/imagpcx.cpp
+++ b/src/common/imagpcx.cpp
@@ -36,7 +36,7 @@
 #include "wx/object.h"
 
 //-----------------------------------------------------------------------------
-// PCX decoding
+// RLE encoding and decoding
 //-----------------------------------------------------------------------------
 
 void RLEencode(unsigned char *p, unsigned int size, wxOutputStream& s)
@@ -76,7 +76,6 @@ void RLEencode(unsigned char *p, unsigned int size, wxOutputStream& s)
         }
     }
 
-
     // Write the last one and return;
     //
     if ((cont > 1) || ((last & 0xC0) == 0xC0))
@@ -120,7 +119,11 @@ void RLEdecode(unsigned char *p, unsigned int size, wxInputStream& s)
 }
 
 
-/* PCX header */
+//-----------------------------------------------------------------------------
+// PCX reading and saving
+//-----------------------------------------------------------------------------
+
+// PCX header
 #define HDR_MANUFACTURER    0
 #define HDR_VERSION         1
 #define HDR_ENCODING        2
@@ -165,8 +168,7 @@ int ReadPCX(wxImage *image, wxInputStream& stream)
     int nplanes;                    // number of planes
     int encoding;                   // is the image RLE encoded?
     int format;                     // image format (8 bit, 24 bit)
-    unsigned int i;
-    off_t pos;
+    unsigned int i, j;
 
     // Read PCX header and check the version number (it must
     // be at least 5 or higher for 8 bit and 24 bit images).
@@ -196,23 +198,19 @@ int ReadPCX(wxImage *image, wxInputStream& stream)
     else
         return wxPCX_INVFORMAT;
 
-    // If the image is of type wxPCX_8BIT, then there is a
-    // palette at the end of the file. Read it now before
-    // proceeding.
-    //
-    if (format == wxPCX_8BIT)
-    {
-        pos = stream.TellI();
-        stream.SeekI(-769, wxFromEnd);
+    // If the image is of type wxPCX_8BIT, then there is
+    // a palette at the end of the image data. If we were
+    // working with a file, we could seek at the end to the
+    // end (SeekI(-769, wxFromEnd) and read the palette
+    // before proceeding. Unfortunately, this would prevent
+    // loading several PCXs in a single stream, so we can't
+    // do it. Thus, 8-bit images will have to be decoded in
+    // two passes: one to read and decode the image data,
+    // and another to replace 'colour indexes' with RGB
+    // values.
 
-        if (stream.GetC() != 12)
-            return wxPCX_INVFORMAT;
 
-        stream.Read(pal, 768);
-        stream.SeekI(pos, wxFromStart);
-    }
-
-    // Allocate memory for a scanline and resize the image.
+    // Resize the image and allocate memory for a scanline.
     //
     image->Create(width, height);
 
@@ -227,7 +225,7 @@ int ReadPCX(wxImage *image, wxInputStream& stream)
     //
     dst = image->GetData();
 
-    for (; height; height--)
+    for (j = height; j; j--)
     {
         if (encoding)
             RLEdecode(p, bytesperline * nplanes, stream);
@@ -240,9 +238,9 @@ int ReadPCX(wxImage *image, wxInputStream& stream)
             {
                 for (i = 0; i < width; i++)
                 {
-                    *(dst++) = pal[ 3 * (p[i]) ];
-                    *(dst++) = pal[ 3 * (p[i]) + 1];
-                    *(dst++) = pal[ 3 * (p[i]) + 2];
+                    // first pass, just store the colour index
+                    *dst = p[i];
+                    dst += 3;
                 }
                 break;
             }
@@ -261,6 +259,28 @@ int ReadPCX(wxImage *image, wxInputStream& stream)
 
     free(p);
 
+    // For 8 bit images, we read the palette, and then do a second
+    // pass replacing indexes with their RGB values;
+    //
+    if (format == wxPCX_8BIT)
+    {
+        unsigned char index;
+
+        if (stream.GetC() != 12)
+            return wxPCX_INVFORMAT;
+
+        stream.Read(pal, 768);
+
+        p = image->GetData();
+        for (unsigned long k = height * width; k; k--)
+        {
+            index = *p;
+            *(p++) = pal[3 * index];
+            *(p++) = pal[3 * index + 1];
+            *(p++) = pal[3 * index + 2];
+        }
+    }
+
     return wxPCX_OK;
 }
 
@@ -278,29 +298,20 @@ int SavePCX(wxImage *image, wxOutputStream& stream)
     unsigned char *src;             // pointer into wxImage data
     unsigned int width, height;     // size of the image
     unsigned int bytesperline;      // bytes per line (each plane)
-    int nplanes;                    // number of planes
-    int format;                     // image format (8 bit, 24 bit)
+    int nplanes = 3;                // number of planes
+    int format = wxPCX_24BIT;       // image format (8 bit, 24 bit)
     wxHashTable h(wxKEY_INTEGER);   // image histogram
-    unsigned long ncolours;         // num. of different colours
     unsigned long key;              // key in the hashtable
     unsigned int i;
- 
-    // Get the histogram of the image, and decide whether to save
-    // as 8 bit or 24 bit, according to the number of colours.
-    //
-    ncolours = image->CountColours(257);
 
-    if (ncolours <= 256)
+    // See if we can save as 8 bit.
+    //
+    if (image->CountColours(256) <= 256)
     {
         image->ComputeHistogram(h);
         format = wxPCX_8BIT;
         nplanes = 1;
     }
-    else
-    {
-        format = wxPCX_24BIT;
-        nplanes = 3;
-    }
 
     // Get image dimensions, calculate bytesperline (must be even,
     // according to PCX specs) and allocate space for one complete
@@ -359,7 +370,7 @@ int SavePCX(wxImage *image, wxOutputStream& stream)
                     key = (r << 16) | (g << 8) | b;
 
                     hnode = (wxHNode *) h.Get(key);
-                    p[i] = hnode->index;
+                    p[i] = (unsigned char)hnode->index;
                 }
                 break;
             }
@@ -374,10 +385,10 @@ int SavePCX(wxImage *image, wxOutputStream& stream)
                 break;
             }
         }
-    
+
         RLEencode(p, bytesperline * nplanes, stream);
     }
-    
+
     free(p);
 
     // For 8 bit images, build the palette and write it to the stream