Re: GD transparency problem

Well, messing with the colour table in each image seems to have done the trick. If you're interested, the results can be seen at: http://www.webvivant.com/features/deptfndr.php Thanks for everyone's help... "James" <james@globalvision.com> wrote in message news:20030512100737.43540.qmail@pb1.pair.com... > I've always found transparency to be crap with 24-32 bit pngs, try > converting the pings down to 8bit and the transparency should stay. > > One other thing you should consider doing is putting the GD stuff as an > image, this way you can load the page , text etc and call the complicated > map process as an image which will "look" better atleast :) > > <img src="myDynamicImage.php?this=that" width=100 height=100> > > You can this kind of thing from the geo mapping system i built here: > http://www.londontown.com/londonmaps/index.php?ID=7643&IV_Type=TotalLondon&I > V_RunByMethod=VBGC&IV_GeoHorizontal=529451&IV_GeoVertical=180462&type=transp > ort&PlotGeoH=529451&PlotGeoV=180462 > > This was a nightmare to build, hundreds of tiles, dynamically trying to find > out which tiles should be obtained to create a single image and then trying > to join them and all the rest of it, yuk! > > > > > "Steve M" <steve.m@wanadoo.fr> wrote in message > news:20030511200950.6492.qmail@pb1.pair.com... > > Just when I thought I was getting a grip on PHP I decide to take on the GD > > library. -sigh- I have two problems which I'll put in two postings, so > > here's the first and here's what I'm trying to do: > > > > I want to display a map and overlay it with highlight sections according > to > > the results of a database search. I tried doing this with floating boxes > and > > GIFs, but had some issues with positioning the whole shebang on the page, > so > > I thought I'd try some GD routines. And it's working to a degree. Having > > converted the files to PNG format, I now use the following code: > > > > $backimg = imagecreatefrompng('deptmaps/bckgrnd.png'); > > for ($i = 1; $i <= $dbrows ; $i++) { > > $overlay[$i] = > imageCreateFromPNG("deptmaps/".$deptcode[$i].".png"); > > imageCopyMerge($backimg,$overlay[$i],0,0,0,0,350,394,10); > > } > > imagepng($backimg,"deptmaps/result.png"); > > echo "<IMG SRC='deptmaps/result.png'>"; > > > > (the $deptcode array holds values from '01' to '95' and there are > > files in > > the deptmaps folder named 01.png etc...) > > > > The problem is that I don't get a clear image overlaid by other clear > > images. The whole thing is rather murky (you can see what I mean at > > http://www.webvivant.com/features/deptfndr.php . Type > > 'or' into the > 'Search > > by name' box and hit 'Find'). > > > > I think the problem lies with the PNG files not retaining their > > transparency. They look fine when I view them in Photoshop, but if I use a > > 'pct' value of 100 I see the last overlay as the desired image on a grey, > > rather than transparent, background. (BTW, I don't really understand that > > 'pct' value - I just tried experimenting with different values). > > > > So here's where I need help from wiser heads. I need a pointer to help me > > investigate this further. Is this a problem with the PNG files? Do I need > to > > edit the colour map, maybe choosing a different transparency value? > > > > Or do I need to play with imagecolortransparent to try to set a new > > transparency value for the image created with imagecreatefrompng? > > > > Any pointers would be appreciated. > > > > > >