+<br><br>Image size:
+<br>Width:
+<input id="image_width" value="300" maxlength="4" size="4" type="number"
+ onchange="checkISValue(this, 'dim'); recalcCoord('Ci', 'scale');">
+Height:
+<input id="image_height" value="300" maxlength="4" size="4" type="number"
+ onchange="checkISValue(this, 'dim'); recalcCoord('Cr', 'scale');">
+<input type="checkbox" id="proportional" onchange="checkProportions();">
+<label for="proportional">proportional</label>
+
+<br><br>Maximum of iterations: