Dynamic Icons

   

The Infographics Dynamic Icons reference page describes all the types of dynamic marker types available.

This page describes how to create a variety of callouts, bubbles, pins, and other graphics that can be requested by URL, or added as markers on top of other charts.

Table of Contents

1. Introduction
   1. Freestanding Icons
   2. Dynamic Markers
2. Common Icon Features
   1. Text Strings
   2. Shadows
3. Contextual Icons

Introduction

The Chart API enables you to create a variety of interesting callouts, pins, or bubbles that mix text and images. These items are called dynamic icons. You can either create a freestanding dynamic icon image, or you can position a dynamic icon on top of your chart as a marker type using the chem parameter. This page will describe how to create dynamic icons as either freestanding images or as markers on another chart. The Infographics Dynamic Icons reference page describes all the types of dynamic marker types available.

The syntax for creating a dynamic icon depends on whether you want a freestanding icon, or as a dynamic marker in another chart.

Freestanding Icons

You can request a dynamic icon image the same way you request any of the other charts. A freestanding dynamic icon supports a different set of parameters than other charts do:

Parameter	Required or Optional	Description
chst=<icon_string_constant>	Required	Describes which kind of icon to create. icon_string_constant - A string constant describing the type of icon to create. See the selection of icons below to choose an icon.
chld=<icon_data>	Required	The specific data used to describe the icon's size, rotation, text, and other required data. icon_data - A set of pipe-delimited values appropriate to the icon. The documentation on this page describes which values are required by each icon type.
cht	NOT USED	Freestanding dynamic icon charts don't use the cht parameter.
chs	NOT USED	Freestanding dynamic icon charts don't use the chs parameter.
chd	NOT USED	Use the chld parameter to pass data to a freestanding dynamic icon.

Example

https://chart.googleapis.com/chart?chst=d_bubble_icon_text_small&chld=ski|bb|Wheeee!|FFFFFF|000000

Dynamic Markers

You can embed a dynamic icon as a marker type on several different types of charts using the chem parameter. See the chem documentation to learn how.

Example

https://chart.googleapis.com/chart?
  chs=300x140
  cht=lc&chco=FF9900,224499
  chd=t:75,74,66,30,10,5,3,1
  chls=1|1
  chem=y;s=bubble_icon_text_small;d=ski,bb,Wheeee!,FFFFFF;dp=2;ds=0
  chm=v,ccccFF,0,::.2,2

Common Icon Features

Most icons can have text strings or shadows associated with them.

Text Strings

All display text passed to the Chart API must be UTF-8 encoded and then URL-encoded. This affects only non-URL-safe characters (URL-safe characters are mostly the English letters a-z both upper and lower case, plus plus a small set of punctuation). For example, the UTF-8 and URL-encoded value for the letter "è" is "%C3%A8", and for the Chinese character 駅 is "%E9%A7%85". Most browsers will let you use an unencoded value in the URL string (for example, 駅) and will encode it for you behind the scenes. However, it is possible that someone viewing your chart URL is using a browser that doesn't do this, so it is usually best to UTF-8 and URL-encode all non-ASCII characters in text strings. Note that this is only for the text shown in bubbles or pins, not for the &, |, or other characters that are part of the URL syntax.

When using the chem parameter to specify dynamic icon markers, you must also escape certain characters in your text, as described in the chem documentation.

Shadows

You can add shadows to many icons, or even draw shadows for some icons without the icon itself!

Shadowed Icons

Many of these icons can be drawn with or without shadows. If shadowing is an option, the icon name will have a version that ends in _withshadow and another version without that ending. You can specify an icon with either ending, depending on whether you want the shadow or not.

Here's an example of a medium text bubble and a pin with and without shadows:

chst=d_bubble_icon_text_big	chst=d_bubble_icon_text_big_withshadow
chst=d_map_pin_icon	chst=d_map_pin_icon_withshadow

Freestanding Shadows

Some icon types allow you to draw their shadow by itself. You might want to do this if you are using several overlapping shadowed icons on a graphic, and they are so close that the shadow from one falls across another icon. For example, here is two shadowed bubbles, Robert drawn first, then Alice:

Note how Alice's shadow partially covers Robert. To fix this, you can draw the Alice shadow first, then the Robert bubble, then Alice without a shadow. Perhaps not totally realistic in terms of lighting and shadows, but it avoids obscuring one bubble with the shadow of another:

chem=
  y;s=bubble_text_small_shadow;d=bb,Alice,FF8,000;ds=0;dp=1;py=1          // Alice, no shadow
  y;s=bubble_text_small_withshadow;d=bbtr,Robert,FF8,000;ds=0;dp=3.5;py=1 // Robert with shadow
  y;s=bubble_text_small;d=bb,Alice,FF8,000;ds=0;dp=1;py=1                 // Alice shadow

All markers specify the same z-order of 1 (py=1), so they are drawn in the order listed, on top of the chart elements (the chart line). First the Alice shadow is drawn, then the Robert bubble on top of that, and finally the Alice bubble on top.

See the documentation of your specific icon type to learn whether you can draw its shadow alone.

Contextual Icons

You can specify an icon that varies its color, size, or stacking according to the point they are assigned to. These icon types are available as dynamic icon markers only (chem parameter), not as freestanding icons.

These icons can be rendered on a series other than the series that specifies their color, size, or stacking information. This means that the chem parameter's ds value specifies the series on which to render the icon, but the values for determining the size or color of the icon are specified in the parameters given below. One good use of this is to use a hidden data series for icon data, but render the icons on a visible line or bar. Here are some examples:

Icon rendered on source series	Icon rendered on non-source series	Icon using hidden series
chem=   y;s=cm_size;ds=0;...;   d=maps_pin,0,10,50,10,8F8,000,hb ds=0 - Render on series 0 (red line) d=maps_pin,0,... - Data from series 0	chem=   y;s=cm_size;ds=1;...;   d=maps_pin,0,10,50,10,8F8,000,hb ds=1 - Render on series 1 (blue line) d=maps_pin,0,... - Data from series 0	chd=t1:   10,20,30,5,10,60   10,20,30,70,60,5 chem=   y;s=cm_size;ds=0;dp=all;   d=disk,1,5,20,5,FFFF10,000 t1: - First series is shown and used line data. All later series are hidden. ds=0 - Markers rendered on series 0. d=disk,1,... - Disk data comes from hidden series 1.

Context Marker Types

Marker Type	chem s Value	Example
Color variation	s=cm_color
Size variation	s=cm_size
Color and size variation	s=cm_color_size
Stacking variation	s=cm_repeat
Stacking and color variation	s=cm_repeat_color

Alignment Strings for Contextual Icons

The contextual icons support an optional alignment string to specify an alignment and offset of the icon to the data point. This string has the following syntax:

<alignment>[+/-<h_anchor_offset>+/-<v_anchor_offset>]

alignment

Two letters describing the alignment of the icon to the point. Examples include tl (top left), and rb (bottom right). See the alignment_string parameter description of the chem parameter for a complete listing and description.

h_anchor_offset

[Optional] The horizontal offset of the anchor point, in pixels. Values including zero must be preceded by either + or -. Important: You must url-encode + as %2B.

v_anchor_offset

[Optional] The vertical offset of the anchor point, in pixels. Values including zero must be preceded by either + or -. Important: You must url-encode + as %2B.

Note that you can also use the of component of the chem parameter to specify horizontal and vertical offsets. If you specify both the of component and h_anchor_offset v_anchor_offset values, all offsets will be applied to your icon.

Examples:

hb-0-0 Horizontal center bottom No offsets	lb-0-0 Bottom left No offsets	rb-0-0 Bottom right No offsets	ht-0-0 Horizontal top No offsets
hb-20-0 Horizontal center bottom -20 horizontal 0 vertical	hb%2b20-0 Horizontal center bottom +20 horizontal 0 vertical	hb-0%2b10 Horizontal center bottom 0 horizontal +10 vertical	hb-0-20 Horizontal center bottom 0 horizontal -20 vertical

Color Variation (cm_color)

You can vary the color of a contextual chart marker according to the point that it represents. You must specify a color range, and the data value will be scaled to a corresponding color within that range.

Syntax

chem=y;s=cm_color;ds=<series_rendering_index>; ...other_values... ;
  d=<icon_shape>,<color_data_series>,<low_color>,<middle_color>,<high_color>,<icon_size>,<outline_color>,<alignment>

<icon_shape>

The icon to use. Specify an ID string identifying one of the images listed at the end of the page.

<color_data_series>

The zero-based index of the data series used to vary the color of the icons.

<low_color>

The low color value in the range, as a three- or six-digit HTML hexadecimal color (no # mark). This is associated with the lowest possible value in the available data range.

<middle_color>

The middle color value in the range, as a three- or six-digit HTML hexadecimal color (no # mark). This is associated with the middle value in the available data range.

<high_color>

The high color value in the range, as a three- or six-digit HTML hexadecimal color (no # mark). This is associated with the highest possible value in the available data range.

<icon_size>

The size of the icon, in pixels. The following values are supported: 12, 16, 24.

<outline_color>

The outline color for the icon, as a three- or six-digit HTML hexadecimal color (no # mark).

<alignment>

An optional string describing the icon alignment and offset.

Example

s=cm_color - color variation icon ds=0 - Render them on data series 0 dp=all - Put an icon on all points. d values: petrol - Icon identifier 0 - Color from data series 0 000,0FF,F55 - Definition of the color scale 24 - Size of icon 000 - Black outlines hv - Align icons on center with the point both horizontally and vertically.

chem=y;s=cm_color;   ds=0;   dp=all;   d=petrol,0,000,0FF,F55,24,000,hv

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Size Variation (cm_size)

You can vary the size alone of a contextual chart marker, according to the data series of your choice.

Syntax

chem=y;s=cm_size;ds=<series_rendering_index>; ...other_values... ;
  d=<icon_type>,<size_data_series>,<zero_value_size>,<size_multiplier>,<min_size>,<outline_color>,<fill_color>,<alignment>

<icon_type>

The shape of the icon. Choose one of the following values: maps_pin, disk, or square.

<size_data_series>

The zero-based index of the data series used to vary the size of the icons.

<zero_value_size>

The base size of the icon, at the minimum data value for the series.

<size_multiplier>

A size scaling factor. This value is multiplied against the difference between each icon's data value and the minimum series value, to calculate the final icon size. Therefore, an icon at the 0 data value will not be affected by this multiplier.

<min_size>

The minimum size for any icon, in pixels.

<outline_color>

The outline color for the icon, as a three- or six-digit HTML hexadecimal color (no # mark).

<fill_color>

The fill color for the icon, as a three- or six-digit HTML hexadecimal color (no # mark).

<alignment>

An optional string describing the icon alignment and offset.

Examples

A basic example. The icon with zero value is rendered at the zero value size, which is 30 pixels. Sizes increase along with the data.

chd=t:0,10,20,30,40,50,60,70 chem=y;s=cm_size;ds=0;dp=all;py=-1;d=maps_pin,0,30,100,10,8F8,000,hb

In this example, the icons take their size data from the yellow line, but are rendered on the blue line. chem=y - Dynamic marker s=cm_size - Size variance ds=1 - Rendered on data series 1 (the blue line) dp=all - Rendered on all points. d= maps_pin - Use a map pin icon 0 - Scale the size according to data series 0 (the yellow line) 10 - Pin size at value 0 90 - Size multiplier 10 - Minimum size 8F8 - Fill color 000 - Outline color hb - Center them horizontally at the bottom of the pin.

chem=chem=y;s=cm_size;ds=1;dp=all;d=maps_pin,0,10,90,10,8F8,000,hb

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Color and Size Variation (cm_color_size)

You can vary both color and size of a contextual chart marker, according to the data series of your choice.

Syntax

chem=y;s=cm_color_size;ds=<series_rendering_index>; ...other_values... ;
  d=<icon_type>,<color_data_series>,<low_color>,<middle_color>,<high_color>,<size_data_series>,<zero_value_size>,<size_multiplier>,<min_size>,<outline_color>,<alignment>

<icon_type>

The shape of the icon. Choose one of the following values: maps_pin, disk, or square.

<color_data_series>

The zero-based index of the data series used to vary the color of the icons.

<low_color>

The low color value in the range, as a three- or six-digit HTML hexadecimal color (no # mark). This is associated with the lowest possible value in the available data range.

<middle_color>

The middle color value in the range, as a three- or six-digit HTML hexadecimal color (no # mark). This is associated with the middle value in the available data range.

<high_color>

The high color value in the range, as a three- or six-digit HTML hexadecimal color (no # mark). This is associated with the highest possible value in the available data range.

<size_data_series>

The zero-based index of the data series used to vary the size of the icons.

<zero_value_size>

The base size of the icon, at the minimum data value for the series.

<size_multiplier>

A size scaling factor. This value is multiplied against the difference between each icon's data value and the minimum series value, to calculate the final icon size. Therefore, an icon at the 0 data value will not be affected by this multiplier.

<min_size>

The minimum size for any icon, in pixels.

<outline_color>

The outline color for the icon, as a three- or six-digit HTML hexadecimal color (no # mark).

<alignment>

An optional string describing the icon alignment and offset.

Examples

This example uses two lines. The pins use color data from the series on which they're rendered, but use size data from the other series. chd=s:0akAZtnkmi,nbMPJOKXXS - First series is used to plot the yellow line and determine the pin color. The second series is used for the blue line, and the pin size. chem=y - Render a dynamic icon s=cm_color_size - Use the color and size variation context icon. ds=1 - Render the items on data series 1, the blue line. dp=all - Put the icon on all points. d= maps_pin - Use the map pin symbol. 1 - Use data series 1 for the pin color. 000,0FF,F55 - The low, medium, and high colors. 0 - Use data series 0 for the pin size. 10 - Pin is 10 pixels at value 0. 90 - A size multiplier of 90. 10 - Minimum pin size of 10 pixels. 000 - Black outline color. hb - Center the pins horizontally along the bottom edge to each data point.

chd=s:0akAZtnkmi,nbMPJOKXXS chem=y;s=cm_color_size;ds=1;dp=all;d=maps_pin,1,000,0FF,F55,0,10,90,10,000,hb

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Stacking Variation (cm_repeat)

You can vary the height of a stack of icons according to the data value at a specific point.

Syntax

chem=y;s=cm_repeat;ds=<series_rendering_index>; ...other_values... ;
  d=<icon_shape>,<repeat_series_index>,<scaling_factor>,<stacking_direction>,<icon_size>,<fill_color>,<outline_color>,<spacing>,<alignment>

<icon_shape>

The icon to use. Specify an ID string identifying one of the images listed at the end of the page.

<repeat_series_index>

The zero-based index of the data series used to calculate how many icons to place at this point.

<scaling_factor>

The source data series value is scaled to a value from 0 to 1 and multiplied by this value to determine how many markers to place on this point. Partial values are truncated.

<stacking_direction>

Stacking direction: either "h" (lowercase) for horizontal or "V" (uppercase) for vertical.

<icon_size>

The size of each marker, in pixels. The following values are supported: 12, 16, 24.

<fill_color>

The fill color for the icon, as a three- or six-digit HTML hexadecimal color (no # mark).

<outline_color>

The outline color for the icon, as a three- or six-digit HTML hexadecimal color (no # mark).

<spacing>

How much space to put between each marker in a stack, in pixels.

<alignment>

An optional string describing the icon alignment and offset.

Example

This example uses a second dummy data series. It is not rendered on the chart, but used as a way to space all the stacks evenly, starting at the bottom of the chart. chd=s1:0akAZtnkmi,AAAAAAAAAA - First series is used to plot the line and determine the stack height. The second is used specify the base of each icon stack, at the 0 value. chem=y - Render a dynamic icon s=cm_repeat - Use the stacking variation context icon. ds=1 - Render the items on data series 1. dp=all - Put the icon on all points. d= d=petrol - Use the petrol symbol. 0 - Use data series 0 for the repeat count. 9 - Use a scaling factor of 6. V - Stack vertically. 16 - Make each marker 16 pixels high. F00 - The icon fill color. 000 - The icon outline color. 2 - Two pixels between each icon in the stack. hb - Center the stacks on the bottom

chd=s1:0akAZtnkmi,AAAAAAAAAA chem=   y;s=cm_repeat;ds=1;dp=all;   d=petrol,0,9,V,16,F00,000,2,hb

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Stacking and Color Variation (cm_repeat_color)

You can vary the both the height and color of an icon stack, according to the data value at a specific point.

Syntax

chem=y;s=cm_repeat_color;ds=<series_rendering_index>; ...other_values... ;
  d=<icon_shape>,<repeat_series_index>,<scaling_factor>,<stacking_direction>,<icon_size>,<color_data_series>,<low_color>,<middle_color>,<high_color>,<outline_color>,<spacing>,<alignment>

<icon_shape>

The icon to use. Specify an ID string identifying one of the images listed at the end of the page.

<repeat_series_index>

The zero-based index of the data series used to calculate how many icons to place at this point.

<scaling_factor>

The source data series value is scaled to a value from 0 to 1 and multiplied by this value to determine how many markers to place on this point. Partial values are truncated.

<stacking_direction>

Stacking direction: either "h" (lowercase) for horizontal or "V" (uppercase) for vertical.

<icon_size>

The size of each marker, in pixels. The following values are supported: 12, 16, 24.

<color_data_series>

The zero-based index of the data series used to vary the color of the icons.

<low_color>

The low color value in the range, as a three- or six-digit HTML hexadecimal color (no # mark). This is associated with the lowest possible value in the available data range.

<middle_color>

The middle color value in the range, as a three- or six-digit HTML hexadecimal color (no # mark). This is associated with the middle value in the available data range.

<high_color>

The high color value in the range, as a three- or six-digit HTML hexadecimal color (no # mark). This is associated with the highest possible value in the available data range.

<outline_color>

The outline color for the icon, as a three- or six-digit HTML hexadecimal color (no # mark).

<spacing>

How much space to put between each marker in a stack, in pixels.

<alignment>

An optional string describing the icon alignment and offset.

Example

chem=y - Render a dynamic icon s=cm_repeat_color - Use the stacking and color variation context icon. ds=0 - Render the items on data series 0. dp=all - Put the icon on all points. d= petrol - Use the petrol symbol. 0 - Use data series 0 for the repeat count. 6 - Use a scaling factor of 6. V - Stack vertically. 12 - Make each marker 12 pixels high. 0 - Use series 0 to specify the color. F00,0F0,00F - The low, middle, and high color values. 000 - The icon outline color. 2 - Two pixels between each icon in the stack. hv - Center the stacks vertically and horizontally on each data point.

chem=   y;s=cm_repeat_color;ds=0;dp=all;   d=petrol,0,6,V,12,0,F00,0F0,00F,000,2,hv

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