PPWIZARD is a free preprocessor for HTML, REXX, Visual Basic or any text files.

GetImageHeightWidth()

This is a rexx function provided by PPWIZARD. This routine (like all PPWIZARD extensions) can be used with any operating system supported by PPWIZARD.

This function can be used to automatically generate the HEIGHT and WIDTH parameters on a html "IMG" tag.

The function takes 3 parameters (the 2nd and 3rd are optional), the parameters are:

1. The name of a file (.GIF, .JPG or .PNG)

2. The width scaling factor (default = "100%").

3. The height scaling factor (default = "?").

4. By default this function now returns the height and width values surrounded by double quotes, if you want the old style (no quotes) then pass 'Y' for this parameter.

5. By default this function caches results so that it does not have to re-read a file if it is used multiple times. The cache is maintained across individual builds for the life of a ppwizard invokation. Pass 'Y' for this parameter if you want to bypass all cache logic.

The scaling factor can be in these formats:

• A number followed by a percentage sign scales the size by the amount specified. "50%" would halve the size while 200% would double it.

• A number on its own (such as "100") fixes the size to the value supplied. It would be a common thing for the other sides size to be specified with "?" to have it scaled down in a proportional manner.

• A "?" causes the side to be sized in the same proportion as the other side.

Note that scaling both sizes of an image by "50%" gives you an image a 1/4 of the size.

If an error occurs the routine aborts, otherwise a string similar to "WIDTH=10 HEIGHT=20" gets returned. If you have one of the supported image types and ppwizard fails to handle it please send it to me zipped so I can update ppwizard as required.

Note that as the image file needs to be read to determine its size this routine will slow down the preprocessing of your files. You could get smart and generate an image header file of sizes (each one #defined) so that a separate slow step generates a header file that html source includes.

Example #1 - IMG Macro

This demonstrates how you can create an "IMG" macro which can take any number of html IMG tag parameters. It generates a HTML image tag with the height and width parameters added:

;--- We will make use of existing functionality -----------------------------
#define   FILEINFO_DEFAULT_PATH ..\     ;;This plus "SRC" value indicates where "LOCAL" file is (build time), in my case it's in "..\graphics"
#include  "FILEINFO.H"

;--- Image Macros -----------------------------------------------------------
#define IMG                                                      \
        ;--- Get image & video information using rexx code --   -\
        #DefineRexx  ''                                         -\
           ;--- Make sure IMG file exists etc ---------------   -\
           <$RexxVerifyLocalInputFile FILE="{$SRC}">;           -\
                                                                -\
           ;--- Get Image Height & Width --------------------   -\
           RxImgHw = GetImageHeightWidth(<$FILEINFO_RXVAR_FULL_LOCAL_FILE>); -\
        #DefineRexx                                             -\
                                                                -\
        ;--- Generate the "IMG" tag -------------------------   -\
        <IMG SRC="{$SRC}" <??RxImgHw>{$? $$PASSDSQ $$SPCPLUS}>

;--- Test macro -------------------------------------------------------------
<$IMG SRC="16x12.gif">
<$IMG ALT="a graphic" SRC="16x12.gif">
<$IMG ALT="a graphic" SRC="16x12.gif" X='Y'>

Example #2

This demonstrates the creation of image tables (using "styles"):

   ;--- Photo macro will either use passed size or work out correct size for you ---
   #define Photo                                                               \
           #evaluate+  LocalFileName    ^"..\graphics\{$Image}"^               \
           #DependsOn  INPUT            "<$LocalFileName>"                     \
           <TR>                                                                \
           #if "{$Size=''}" <> ""                                              \
               #define+   TmpSize {$Size=''}     ;;User supplied size          \
           #elseif                                                             \
               #evaluate+ TmpSize ^GetImageHeightWidth("<$LocalFileName>")^    \
           #endif                                                              \
           <TD ALIGN=CENTER>                                                   \
           <IMG SRC="graphics/clear1x1.gif" WIDTH=1 HEIGHT=1 VSPACE=20>        \
           {$Title}<BR><BR>                                                    \
           <IMG SRC="graphics/{$Image}" BORDER=0 <$TmpSize> ALT="{$Title}">    \
           <IMG SRC="graphics/clear1x1.gif" WIDTH=1 HEIGHT=1 VSPACE=20>        \
           </TR>

    ;--- Create table of photos --------------------------------------------
    <BR><CENTER><TABLE COLS=1 BORDER=10 CELLSPACING=10>
       <TR>
       <TH ALIGN=CENTER>Pictures
       </TR>

       ;--- Include all my photos ------------------------------------------
       <$Photo Image="lazy.jpg"     Title="Watching TV">
       <$Photo Image="carback.jpg"  Title="New Car (Back Left)">
    </TABLE></CENTER>

Example #3

This example shows how you can manipulate the format of the height and width text, this example produces "width,height":

;--- Define macro which creates 'new Image(W,H);' text ----------------------
#defineRexx '_ImageWidthCommaHeight_'
   ;--- Get heigth and width for image (seperated them from fixed text) -----
   parse value GetImageHeightWidth("{$IMAGE}") with 'WIDTH="' iWidth '" HEIGHT="' iHeight '"'

   ;--- Format the information the way we need it ---------------------------
   iWidthHeight = iWidth || ',' || iHeight;
#defineRexx
#define ImageWidthCommaHeight                             \
        #evaluate ^^ ^<$_ImageWidthCommaHeight_ {$?}>^   -\
        <??iWidthHeight>

;--- Test macro -------------------------------------------------------------
JsVar = new Image(<$ImageWidthCommaHeight IMAGE="graphics\ppw_bg.jpg">);

PPWIZARD Manual

Thursday January 17 2002 at 6:27pm