GDChart Standard Options

Option Name	Type	Default Value	Notes
GDC_title	char *	NULL	Chart Title Top, Centered newlines '\n' allowed
GDC_ytitle	char *	NULL	Title along the Y axis
GDC_xtitle	char *	NULL	Title along the X axis
GDC_ytitle2	char *	NULL	Title along the right-hand Y axis
GDC_title_size	enum GDC_font_size	GDC_MEDBOLD
GDC_ytitle_size	enum GDC_font_size	GDC_MEDBOLD
GDC_xtitle_size	enum GDC_font_size	GDC_MEDBOLD
GDC_yaxisfont_size	enum GDC_font_size	GDC_SMALL	Y axis label font size
GDC_xaxisfont_size	enum GDC_font_size	GDC_SMALL	X axis label font size
GDC_ylabel_fmt	char *	NULL	default: fractions (1/2n) printf fmt'ing, e.g.: "%.2f"
GDC_ylabel2_fmt	char *	NULL	''
GDC_xlabel_spacing	short	5	pixels between each X label MAXSHORT means force all
GDC_ylabel_density	char	80	%
GDC_requested_ymin	float	GDC_NOVALUE	min value to use for Y scaling (may be overridden by data)
GDC_requested_ymax	float	GDC_NOVALUE	max ''
GDC_requested_yinterval	float	GDC_NOVALUE	Y axis label intervals (may be overridden, if they don't fit)
GDC_0Shelf	char	TRUE	line at Y=0, if applicable
GDC_grid	char	TRUE
GDC_xaxis	char	TRUE
GDC_yaxis	char	TRUE
GDC_yaxis2	char	TRUE
GDC_yval_style	char	TRUE	unused
GDC_stack_type	GDC_STACK_T	GDC_STACK_DEPTH	Applicable only to multiple datasets
GDC_3d_depth	float	5.0	% total gif size
GDC_3d_angle	unsigned char	45o	1-89o
GDC_bar_width	unsigned char	75	% width of X interval
GDC_HLC_style	GDC_HLC_STYLE_T	GDC_HLC_CLOSE_CONNECTED	Applicable only to HiLowClose chart types
GDC_HLC_cap_width	unsigned char	25	%
GDC_annotation	GDC_ANNOTATION_T *	NULL
GDC_annotation_font_size	enum GDC_font_size	GDC_SMALL
GDC_num_scatter_pts	int	0
GDC_scatter	GDC_SCATTER_T *	NULL
GDC_thumbnail	char	FALSE	unused
GDC_thumblabel	char *	NULL	unused
GDC_thumbval	float	-MAXFLOAT	unused
GDC_border	char	TRUE	border around the chart Changed to GDC_BORDER_T type in v0.95
GDC_BGColor	unsigned long	0x000000L	Background color1
GDC_GridColor	unsigned long	0xA0A0A0L	1
GDC_LineColor	unsigned long	GDC_DFLTCOLOR	1 2
GDC_PlotColor	unsigned long	GDC_DFLTCOLOR	1 2
GDC_VolColor	unsigned long	0xA0A0FFL	1
GDC_TitleColor	unsigned long	GDC_DFLTCOLOR	1 2
GDC_XTitleColor	unsigned long	GDC_DFLTCOLOR	1 2
GDC_YTitleColor	unsigned long	GDC_DFLTCOLOR	1 2
GDC_YTitle2Color	unsigned long	GDC_DFLTCOLOR	1 2
GDC_XLabelColor	unsigned long	GDC_DFLTCOLOR	1 2
GDC_YLabelColor	unsigned long	GDC_DFLTCOLOR	1 2
GDC_YLabel2Color	unsigned long	GDC_DFLTCOLOR	1 2
GDC_SetColor	unsigned long *	NULL	color1 of entire set of data (unsigned long*)array[num sets] supersedes GDC_PlotColor
GDC_ExtColor	unsigned long *	NULL	color1 individual data items (unsigned long*)array[num sets][num points] supersedes GDC_SetColor
GDC_ExtVolColor	unsigned long *	NULL	secondary data individual point plot color1 (unsigned long*)array[num points] supersedes GDC_VolColor
GDC_transparent_bg	char	FALSE	Transparent background
GDC_BGImage	char *	NULL	GIF File name to be used as background image
Blue: available only in v0.9.5 & v0.10 or higher
GDC_image_type	GDC_image_type_t	GDC_GIF	GIF, PNG, JPEG, WBMP available. (v0.10.1+ only)
GDC_INTERP	float		Not actually an option GDChart allows 'missing' data within charts via the data value GDC_NOVALUE. V0.951+ missing data can be filled in with linear interpolated values via the data value GDC_INTERP
GDC_border	GDC_BORDER_T	GDC_BORDER_ALL	Control over chart borders. NONE, ALL, X, Y, Y2, TOP. Can be OR'd
GDC_grid *	GDC_TICK_T	GDC_TICK_LABELS	Control over X grid lines.
GDC_ticks *	GDC_TICK_T	GDC_TICK_LABELS	Control over X tick marks. LABELS, POINTS, NONE
GDC_xlabel_ctl	char *	NULL	char array[num points] of TRUE, FALSE Control over X labels.
Purple: available only in v0.11 or higher
GDC_xaxis_angle	double	90.0	Angle in degress for the X-axis lables. 0-90o. 0=horizontal 90=vertical If TTFs are not used only 0 and 90 are available, TTFs can be drawn "slanted", i.e., 1-89o
GDC_title_font GDC_ytitle_font GDC_xtitle_font GDC_yaxis_font GDC_xaxis_font GDC_annotation_font	char *	NULL	Name of font to use. 3 The fontname is the full pathname to a TrueType font file, or a font face name if the GDFONTPATH environment variable or FreeType's DEFAULT_FONTPATH variable have been set intelligently.
GDC_title_ptsize GDC_ytitle_ptsize GDC_xtitle_ptsize GDC_yaxis_ptsize GDC_xaxis_ptsize GDC_annotation_ptsize	double	0.0	Font Point size 3

All options are defaulted and optional. I.e., none need be set by the calling application.
[For now] all options are global, and owned by the client, not the lib. This will likely change in a future release.
'Vol', "right-hand" axis, 'label2', 'secondary', etc. all refer to the right hand axis.
¹ Colors are specified as RGB in hex. E.g., 0x8080FF would be light blue.
² GDC_DFLTCOLOR results in an "opposite" color of the background color.
³ Available only if built with FreeType support.
^* Type supported will likely change to MAJOR/MINOR values.