This example uses DrawMessage to produce a warning message image instead of a plot image. In a real application, a PHPlot object would be created and set up for plotting, then some condition in the application code would determine that a plot could not be produced. Instead of producing a plot image, DrawMessage could be used to provide an image (as expected by the containing HTML page) with a message for the user.
The options supplied to DrawMessage in this example indicate that:
The image background should be drawn, rather than using a plain white background.
The image border should be drawn too.
Fonts should not be reset, allowing the custom setting for the
genericfont to be used.The text should be word-wrapped at 50 columns. The narrower wrap point is needed due to the larger font. Note that newlines in the text are preserved, and long lines are wrapped.
The specified color (navy) should be used for the message text.
Note: This example uses a system-dependent TrueType font, and will need to be modified for other systems.
The DrawMessage function was added in PHPlot-5.7.0.
Example 5.42. DrawMessage
<?php
# PHPlot Example: Use DrawMessage() to display a message
require_once 'phplot.php';
$plot = new PHPlot(600, 400);
# Note: This font name is system dependent:
$plot->SetFontTTF('generic', 'LiberationSans-Italic.ttf', 14);
$plot->SetBackgroundColor('#ffcc99');
$plot->SetImageBorderWidth(8);
$plot->SetImageBorderColor('blue');
$plot->SetImageBorderType('raised');
#
# Here you would start to produce the plot, then detect something wrong ...
#
$message = "I'm sorry, Dave. I'm afraid I can't do that.\n"
. "\n"
. "You haven't supplied enough data to produce a plot. "
. "Please try again at another time.";
$plot->DrawMessage($message, array(
'draw_background' => TRUE,
'draw_border' => TRUE,
'reset_font' => FALSE,
'wrap_width' => 50,
'text_color' => 'navy'));