PLCOLORBAR(3plplot)

📦
version 5.15.0 · 12 versions
, in ubuntu stonking

🎨 PLCOLORBAR (3plplot) — the color bar glow-up ✨

okay so bestie, we're in PLplot API land and this one is literally the function that makes your image/shade/gradient plot look like it has its life together 💅

🌸 NAME 🌸

plcolorbar — plot a color bar for image, shade or gradient plots. that's it, that's the icon.

✨ SYNOPSIS ✨

plcolorbar(p_colorbar_width, p_colorbar_height, opt, position, x, y,
x_length, y_length, bg_color, bb_color, bb_style, low_cap_color,
high_cap_color, cont_color, cont_width, n_labels, label_opts, labels,
naxes, axis_opts, ticks, sub_ticks, n_values, values)

💖 DESCRIPTION 💖

so this routine creates a continuous color bar for image, shade, or gradient plots. (and if you were wondering — yes, pllegend(3plplot) is the sister function for legends with discrete elements, iykyk.) the arguments of plcolorbar give you control over the location and size of the color bar and the location and characteristics of the elements inside it (most of which are optional). the resulting color bar gets clipped at the boundaries of the current subpage — no cap, no cap 🧢. (N.B. the adopted coordinate system used for some of the parameters is defined in the documentation of the position parameter, so go read that one, fr fr.)

Redacted form: plcolorbar(p_colorbar_width, p_colorbar_height, opt, position, x, y, x_length, y_length, bg_color, bb_color, bb_style, low_cap_color, high_cap_color, cont_color, cont_width, label_opts, labels, axis_opts, ticks, sub_ticks, values)

This function is used in examples 16 and 33. 🫶

👑 ARGUMENTS 👑

  • p_colorbar_width (PLFLT_NC_SCALAR(3plplot), output) — the returned value of the labelled and decorated color bar width, in adopted coordinates. she's giving measurements 💅
  • p_colorbar_height (PLFLT_NC_SCALAR(3plplot), output) — the returned value of the labelled and decorated color bar height, in adopted coordinates.
  • opt (PLINT(3plplot), input) — opt contains the bits controlling the overall color bar. the orientation (direction of the maximum value) of the color bar is specified with PL_ORIENT_RIGHT, PL_ORIENT_TOP, PL_ORIENT_LEFT, or PL_ORIENT_BOTTOM. if none of these bits are specified, the default orientation is toward the top if the colorbar is placed on the left or right of the viewport, or toward the right if the colorbar is placed on the top or bottom of the viewport. if the PL_COLORBAR_BACKGROUND bit is set, plot a (semitransparent) background for the color bar ✨. if the PL_COLORBAR_BOUNDING_BOX bit is set, plot a bounding box for the color bar. the type of color bar must be specified with one of PL_COLORBAR_IMAGE, PL_COLORBAR_SHADE, or PL_COLORBAR_GRADIENT — and if more than one of those bits is set, only the first one in the above list is honored (sorry bestie, no mixing). the position of the (optional) label/title can be specified with PL_LABEL_RIGHT, PL_LABEL_TOP, PL_LABEL_LEFT, or PL_LABEL_BOTTOM. if no label position bit is set then no label will be drawn. if more than one of this list of bits is specified, only the first one on the list is honored. end-caps for the color bar can be added with PL_COLORBAR_CAP_LOW and PL_COLORBAR_CAP_HIGH — if a particular color bar cap option is not specified then no cap will be drawn for that end. as a special case for PL_COLORBAR_SHADE, the option PL_COLORBAR_SHADE_LABEL can be specified: if this option is provided then any tick marks and tick labels will be placed at the breaks between shaded segments. TODO: this should be expanded to support custom placement of tick marks and tick labels at custom value locations for any color bar type. (not me reading the TODO in the manpage 😭)
  • position (PLINT(3plplot), input) — position contains bits which control the overall position of the color bar and the definition of the adopted coordinates used for positions, just like what is done for the position argument for pllegend(3plplot). however, note that the defaults for the position bits (see below) are different than the pllegend(3plplot) case 👀. the combination of the PL_POSITION_LEFT, PL_POSITION_RIGHT, PL_POSITION_TOP, PL_POSITION_BOTTOM, PL_POSITION_INSIDE, and PL_POSITION_OUTSIDE bits specifies one of the 16 possible standard positions (the 4 corners and centers of the 4 sides, for both the inside and outside cases) of the color bar relative to the adopted coordinate system. the corner positions are specified by the appropriate combination of two of the PL_POSITION_LEFT, PL_POSITION_RIGHT, PL_POSITION_TOP, and PL_POSITION_BOTTOM bits, while the sides are specified by a single value of one of those bits. the adopted coordinates are normalized viewport coordinates if the PL_POSITION_VIEWPORT bit is set, or normalized subpage coordinates if the PL_POSITION_SUBPAGE bit is set. default position bits: if none of PL_POSITION_LEFT, PL_POSITION_RIGHT, PL_POSITION_TOP, or PL_POSITION_BOTTOM are set, then use PL_POSITION_RIGHT. if neither of PL_POSITION_INSIDE or PL_POSITION_OUTSIDE is set, use PL_POSITION_OUTSIDE. if neither of PL_POSITION_VIEWPORT or PL_POSITION_SUBPAGE is set, use PL_POSITION_VIEWPORT.
  • x (PLFLT(3plplot), input) — X offset of the color bar position in adopted coordinates from the specified standard position of the color bar. for positive x, the direction of motion away from the standard position is inward/outward from the standard corner positions or standard left or right positions if the PL_POSITION_INSIDE/PL_POSITION_OUTSIDE bit is set in position. for the standard top or bottom positions, the direction of motion is toward positive X. 🦋
  • y (PLFLT(3plplot), input) — Y offset of the color bar position in adopted coordinates from the specified standard position of the color bar. for positive y, the direction of motion away from the standard position is inward/outward from the standard corner positions or standard top or bottom positions if the PL_POSITION_INSIDE/PL_POSITION_OUTSIDE bit is set in position. for the standard left or right positions, the direction of motion is toward positive Y.
  • x_length (PLFLT(3plplot), input) — length of the body of the color bar in the X direction, in adopted coordinates.
  • y_length (PLFLT(3plplot), input) — length of the body of the color bar in the Y direction, in adopted coordinates.
  • bg_color (PLINT(3plplot), input) — the cmap0 color of the background for the color bar (PL_COLORBAR_BACKGROUND).
  • bb_color (PLINT(3plplot), input) — the cmap0 color of the bounding-box line for the color bar (PL_COLORBAR_BOUNDING_BOX).
  • bb_style (PLINT(3plplot), input) — the pllsty(3plplot) style number for the bounding-box line for the color bar (PL_COLORBAR_BACKGROUND). (yes, that's what it says — copying it verbatim bestie 🙈)
  • low_cap_color (PLFLT(3plplot), input) — the cmap1 color of the low-end color bar cap, if it is drawn (PL_COLORBAR_CAP_LOW).
  • high_cap_color (PLFLT(3plplot), input) — the cmap1 color of the high-end color bar cap, if it is drawn (PL_COLORBAR_CAP_HIGH).
  • cont_color (PLINT(3plplot), input) — the cmap0 contour color for PL_COLORBAR_SHADE plots. this is passed directly to plshades(3plplot), so it will be interpreted according to the design of plshades(3plplot).
  • cont_width (PLFLT(3plplot), input) — contour width for PL_COLORBAR_SHADE plots. this is passed directly to plshades(3plplot), so it will be interpreted according to the design of plshades(3plplot).
  • n_labels (PLINT(3plplot), input) — number of labels to place around the color bar.
  • label_opts (PLINT_VECTOR(3plplot), input) — a vector of options for each of n_labels labels.
  • labels (PLCHAR_MATRIX(3plplot), input) — a vector of n_labels UTF-8 character strings containing the labels for the color bar. ignored if no label position is specified with one of the PL_COLORBAR_LABEL_RIGHT, PL_COLORBAR_LABEL_TOP, PL_COLORBAR_LABEL_LEFT, or PL_COLORBAR_LABEL_BOTTOM bits in the corresponding label_opts field. 💀 (so don't come crying when your labels don't show, the bits weren't set)
  • n_axes (PLINT(3plplot), input) — number of axis definitions provided. this value must be greater than 0. it is typically 1 (numerical axis labels are provided for one of the long edges of the color bar), but it can be larger if multiple numerical axis labels for the long edges of the color bar are desired. main character energy for the multidimensional girlies ✨
  • axis_opts (PLCHAR_MATRIX(3plplot), input) — a vector of n_axes ascii character strings containing options (interpreted as for plbox(3plplot)) for the color bar's axis definitions.
  • ticks (PLFLT_VECTOR(3plplot), input) — a vector of n_axes values of the spacing of the major tick marks (interpreted as for plbox(3plplot)) for the color bar's axis definitions.
  • sub_ticks (PLINT_VECTOR(3plplot), input) — a vector of n_axes values of the number of subticks (interpreted as for plbox(3plplot)) for the color bar's axis definitions.
  • n_values (PLINT_VECTOR(3plplot), input) — a vector containing the number of elements in each of the n_axes rows of the values matrix.
  • values (PLFLT_MATRIX(3plplot), input) — a matrix containing the numeric values for the data range represented by the color bar. for a row index of i_axis (where 0 < i_axis < n_axes), the number of elements in the row is specified by n_values[i_axis]. for PL_COLORBAR_IMAGE and PL_COLORBAR_GRADIENT the number of elements is 2, and the corresponding row elements of the values matrix are the minimum and maximum value represented by the colorbar. for PL_COLORBAR_SHADE, the number and values of the elements of a row of the values matrix is interpreted the same as the nlevel and clevel arguments of plshades(3plplot). 🍓

🧚 AUTHORS 🧚

Many developers (who are credited at http://plplot.sourceforge.net/credits.php) have contributed to PLplot over its long history. absolute legends, all of them 👑

🌈 SEE ALSO 🌈

PLplot documentation at http://plplot.sourceforge.net/documentation.php.

okay that's the whole vibe check, bestie — keep every bit exactly as written, go build that gorgeous color bar, and remember: slay ✨💅🦋

source/version: PLplot API, page PLCOLORBAR(3plplot) — dated August, 2026. that's a wrap, ily, bye 🫶🎀

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