Misc. typos

Some are user facing. Some are in actual code. Most are in source comments. Also, please double check the changes in contrib/tools/pngfix.c

contrib/examples/iccfrompng.c

@@ -10,7 +10,7 @@
  * without processing the image.  Notice that some header information may occur
  * after the image data. Textual data and comments are an example; the approach
  * in this file won't work reliably for such data because it only looks for the
- * information in the section of the file that preceeds the image data.
+ * information in the section of the file that precedes the image data.
  *
  * Compile and link against libpng and zlib, plus anything else required on the
  * system you use.

contrib/libtests/pngimage.c

@@ -927,7 +927,7 @@ update_display(struct display *dp)
    png_structp pp;
    png_infop   ip;
 
-   /* Now perform the initial read with a 0 tranform. */
+   /* Now perform the initial read with a 0 transform. */
    read_png(dp, &dp->original_file, "original read", 0/*no transform*/);
 
    /* Move the result to the 'original' fields */

contrib/libtests/pngstest.c

@@ -1142,7 +1142,7 @@ get_pixel(png_uint_32 format))(Pixel *p, png_const_voidp pb)
    }
 }
 
-/* Convertion between pixel formats.  The code above effectively eliminates the
+/* Conversion between pixel formats.  The code above effectively eliminates the
  * component ordering changes leaving three basic changes:
  *
  * 1) Remove an alpha channel by pre-multiplication or compositing on a

contrib/libtests/pngvalid.c

@@ -5001,7 +5001,7 @@ standard_display_init(standard_display *dp, png_store* ps, png_uint_32 id,
    dp->npalette = 0;
    /* Preset the transparent color to black: */
    memset(&dp->transparent, 0, sizeof dp->transparent);
-   /* Preset the palette to full intensity/opaque througout: */
+   /* Preset the palette to full intensity/opaque throughout: */
    memset(dp->palette, 0xff, sizeof dp->palette);
 }
 
@@ -9746,7 +9746,7 @@ gamma_component_validate(const char *name, const validate_info *vi,
        *
        * pngvalid calculations:
        *  input_sample: linear result; i linearized and composed, range 0..1
-       *  encoded_sample: encoded result; input_sample scaled to ouput bit depth
+       *  encoded_sample: encoded result; input_sample scaled to output bit depth
        *
        * libpng calculations:
        *  output: linear result; od scaled to 0..1 and linearized
@@ -10183,10 +10183,10 @@ gamma_image_validate(gamma_display *dp, png_const_structp pp,
     * Since the library must quantize the output to 8 or 16 bits there is
     * a fundamental limit on the accuracy of the output of +/-.5 - this
     * quantization limit is included in addition to the other limits
-    * specified by the paramaters to the API.  (Effectively, add .5
+    * specified by the parameters to the API.  (Effectively, add .5
     * everywhere.)
     *
-    * The behavior of the 'sbit' paramter is defined by section 12.5
+    * The behavior of the 'sbit' parameter is defined by section 12.5
     * (sample depth scaling) of the PNG spec.  That section forces the
     * decoder to assume that the PNG values have been scaled if sBIT is
     * present:
@@ -11729,7 +11729,7 @@ int main(int argc, char **argv)
 
    /* Some default values (set the behavior for 'make check' here).
     * These values simply control the maximum error permitted in the gamma
-    * transformations.  The practial limits for human perception are described
+    * transformations.  The practical limits for human perception are described
     * below (the setting for maxpc16), however for 8 bit encodings it isn't
     * possible to meet the accepted capabilities of human vision - i.e. 8 bit
     * images can never be good enough, regardless of encoding.

contrib/libtests/tarith.c

@@ -176,7 +176,7 @@ int validation_ascii_to_fp(int count, int argc, char **argv)
       }
       else if (PNG_FP_IS_POSITIVE(state) && !(test > 0))
       {
-         fprintf(stderr, "%g[%d] -> '%s' but postive value not so reported\n",
+         fprintf(stderr, "%g[%d] -> '%s' but positive value not so reported\n",
             test, precision, buffer);
          failed = 1;
          assert(!PNG_FP_IS_NEGATIVE(state));

contrib/pngminus/README

@@ -17,7 +17,7 @@ express or implied warranty.
 Some history
 ------------
 Soon after the creation of PNG in 1995, the need was felt for a set of
-pnmtopng / pngtopnm utilities. Independantly Alexander Lehmann and I
+pnmtopng / pngtopnm utilities. Independently Alexander Lehmann and I
 (Willem van Schaik) started such a project. Luckily we discovered this
 and merged the two together into pnmtopng.tar.gz, which is available
 from a/o ftp://ftp.simplesystems.org/pub/libpng/png/.

contrib/tools/pngcp.c

@@ -2117,7 +2117,7 @@ better_options(const struct display *dp)
     *
     * This function looks through the stack from the bottom up looking for an
     * option that does not match the current best value.  When it finds one it
-    * checks to see if it is more or less desireable and returns true or false
+    * checks to see if it is more or less desirable and returns true or false
     * as appropriate.
     *
     * Notice that this means that the order options are pushed onto the stack

contrib/tools/pngfix.c

@@ -2664,7 +2664,7 @@ zlib_check(struct file *file, png_uint_32 offset)
              * this case, so do the optimization anyway.
              */
             if (zlib.cksum)
-               chunk_message(zlib.chunk, "zlib checkum");
+               chunk_message(zlib.chunk, "zlib checksum");
             break;
 
 
@@ -3678,7 +3678,7 @@ usage(const char *prog)
    size_t i;
    static const char *usage_string[] = {
 "  Tests, optimizes and optionally fixes the zlib header in PNG files.",
-"  Optionally, when fixing, strips ancilliary chunks from the file.",
+"  Optionally, when fixing, strips ancillary chunks from the file.",
 0,
 "OPTIONS",
 "  OPERATION",

contrib/visupng/VisualPng.c

@@ -716,7 +716,7 @@ BOOL DisplayImage (HWND hwnd, BYTE **ppDib,
     png_color                   bkgGray  = {127, 127, 127};
     png_color                   bkgWhite = {255, 255, 255};
 
-    /* allocate memory for the Device Independant bitmap */
+    /* allocate memory for the Device Independent bitmap */
 
     wDIRowBytes = (WORD) ((3 * cxWinSize + 3L) >> 2) << 2;