Changes between Initial Version and Version 1 of PHPMapScriptDynamicLine

Timestamp:

Jan 27, 2009, 9:48:34 AM (15 years ago)

Author:

jmckenna

Comment:

--

PHPMapScriptDynamicLine

@@ +1 @@
+= Adding Dynamic Lines with PHPMapScript =
+
+Here we have another sample code to illustrate the usage of PHPMapScript. It allows an user to draw a line on the fly. Each time the user clicks on the image it is added that point to a line, then the line is drawn on the map.
+
+Basically, the tasks this script does are:
+
+   1. Create the map
+   2. Create a line
+   3. Add last point to the line
+   4. Create the shape
+   5. Add the line to the shape
+   6. Add the shape to the layer
+   7. Draw the map 
+
+This is the layer "lines" used in the code:
+{{{
+  LAYER
+    GROUP "user"
+    NAME "lines"
+    TYPE line
+    STATUS on
+   CLASS
+       NAME "0"
+       TEMPLATE "ttt_query.html"
+       STYLE
+         COLOR 255 0 0 # red
+       END #style
+   END #class
+  END #layer
+}}}
+== PHP code ==
+
+The file is called query3.php
+{{{
+<?php
+
+dl('php_mapscript.so');
+//dl('php_mapscript_42.dll'); //For WinDoS Users
+
+//Convert pixels to map units got from PHPMapscriptSnippet1
+function click2map ($click_x, $click_y) {
+    global $map;
+    $e= &$map->extent; //Tip for saving type time
+    $x_pct = ($click_x / $map->width);
+    $y_pct = 1 - ($click_y / $map->height);
+    $x_map = $e->minx + ( ($e->maxx - $e->minx) * $x_pct);
+    $y_map = $e->miny + ( ($e->maxy - $e->miny) * $y_pct);
+
+    return array($x_map, $y_map);
+}
+
+
+// --------------- MAIN -----------------------
+
+$map= ms_newMapObj('data/test2.map');
+
+//Avoid register global=Off (that way it is not neccesary use $_POST[])
+import_request_variables("gP", "");
+
+if (isset($image_x) && isset($image_y)){
+    //Convert pixels to map units
+    $map_pt = click2map($image_x,$image_y);
+
+    //Construct the line
+    $line = ms_newLineObj();
+    $line->addXY($map_pt[0],$map_pt[1]);
+    if (is_array($prev_x)) { //Add points of the hidden input fields
+        foreach ($prev_x as $i => $x){
+            $line->addXY($x, $prev_y[$i]);
+        }
+    }
+    //Create the shape object that will be added to the layer
+    $shp = ms_newShapeObj(MS_SHAPE_LINE);
+    $shp-> add($line);
+
+    $layer = $map->getLayerByName('lines');
+    $layer->addFeature($shp);
+}
+//Draw the map
+$img = $map->draw();
+$url = $img->saveWebImage();
+
+//Now add hidden fields to the form
+for($i=0;$i<$line->numpoints;$i++) {
+    $pt = $line->point($i);
+    $x = $pt->x;
+    $y = $pt->y;
+    $HTML_HIDDEN.="<input type=\"hidden\" name=\"prev_x[$i]\" value=\"$x\"/>";
+    $HTML_HIDDEN.="<input type=\"hidden\" name=\"prev_y[$i]\" value=\"$y\"/>";
+}
+?>
+
+< html>< head>< title>Yapig</ title></ head>
+<!--remove white spaces of the HTML tags -->
+< body>
+<form method="post" action="query3.php" >
+   <input style="border:thin solid black;"type="image" name="image" src="<?php echo $url ?>" />
+     <?php echo $HTML_HIDDEN ?>
+</form>
+<a href="query3.php">Clear</a>
+ </ body>
+</ html>
+}}}
+-- Merlos
+
+Go to [wiki:PHPMapScript]