geom_arrow. Parametrization of ggplot2::geom_segment either by location and displacement or by magnitude and angle with default arrows. geom_arrow

 
 Parametrization of ggplot2::geom_segment either by location and displacement or by magnitude and angle with default arrowsgeom_arrow  5

The start and end locations of the genes within their molecule (s) are mapped to the xmin and xmax aesthetics respectively. to control graphics. geom_relief() and geom_shadow() now don’t have a size aesthetic, since they shouldn’t have had it anyway. then come thes aesthetics, set in the aes () function. ggplot2 geom_line() arrow direction between specific values. . Source: R/geom-function. This is done to allow, e. This was ugly and bad and didn’t work in most cases, so I threw together some hacks to make it work,. All text drawing options available in ggfittext::geom_fit_text () (growing, reflowing, etc. fill = NULL, lineend = "butt", linejoin = "round", na. geom_arrow: Arrows; geom_contour2: 2d contours of a 3d surface; geom_contour_fill: Filled 2d contours of a 3d surface; geom_contour_tanaka: Illuminated contours; geom_relief: Relief Shading; geom_streamline: Streamlines; geom_text_contour: Label contours; geopotential: Geopotential height; GeostrophicWind: Calculate. geom_arrow: Arrows; geom_contour2: 2d contours of a 3d surface; geom_contour_fill: Filled 2d contours of a 3d surface; geom_contour_tanaka: Illuminated contours; geom_relief: Relief Shading; geom_streamline: Streamlines; geom_text_contour: Label contours; geopotential: Geopotential height; GeostrophicWind: Calculate. frame containing the variable using the $ operator. Basic scatter plots. arrangeGrobByParsingLegend: Arrange grobs by parse their legend. g. It adds arrows in. Arrow specification, as created by grid::arrow(). arrow: Arrow. LonLabel() LatLabel() Label longitude and latitude# ' @param geom The geometry used to display the data. Example 1: Add Single Line Segment to ggplot2 Plot. reverselog_trans() Reverse log transform. geom_line() connects them in order of the variable on the x axis. # ' @param. I have multiple years of data in individual rows and want an arrow pointing from the earliest data point to the. It is available from Bioconductor. There are many different ways to use R to plot line graphs, but the one I prefer is the ggplot geom_line function. name: The name of the scale. They may also be parameters to the paired geom/stat. New functions Laplacian(), Divercence() and Vorticity() DerivatePhysical() is removed since it was made redundant by the. Details. geom_arrow () is the same as geom_vector () but defaults to preserving the direction under coordinate transformation and different plot ratios. This was ugly and bad and didn’t work in most cases, so I threw together some hacks to make it work,. Instead, metR‘s geom_vector() and geom_arrow() draw vectors defined by their lateral displacements (dx, dy) or their magnitude and. Before ggplot2 introduced geom_contour_filled(), the ‘canonical’ way to get filled contours was by using stat_contour() with a polygon geom and mapping fill to level (see this issue). g. To add something useful to the answer @hrbrmstr gave, I think both geom_segment() and geom_curve() are unnecessarily limited in that they don't let you specify the arrow fill color separately from the arrow outline. geom_contour_fill() This geom has a bit of a long story. linejoin: Line join style (round, mitre, bevel). If grid = TRUE, x. See the underlying drawing function grid::curveGrob () for the parameters that control the curve. All you need to do is supply a stars. font, awt. The error comes from the xned argument. lineend: Line end style (round, butt, square). geom_arrow: Arrows; geom_contour2: 2d contours of a 3d surface; geom_contour_fill: Filled 2d contours of a 3d surface; geom_contour_tanaka: Illuminated contours; geom_relief: Relief Shading; geom_streamline: Streamlines; geom_text_contour: Label contours; geopotential: Geopotential height; GeostrophicWind: Calculate. North arrow styles. 9001. lineend. labelsize: the size of labels. frame (x = c (0, 1)), aes (x = x)) + geom. Read more . geom_arrow: Arrows; geom_contour2: 2d contours of a 3d surface; geom_contour_fill: Filled 2d contours of a 3d surface; geom_contour_tanaka: Illuminated contours; geom_relief: Relief Shading; geom_streamline: Streamlines; geom_text_contour: Label contours; geopotential: Geopotential height; GeostrophicWind: Calculate. ggplot2::ggplot (example_genes, ggplot2::aes (xmin = start, xmax = end, y = molecule, fill = gene)) + geom_gene_arrow () + ggplot2::facet_wrap (~ molecule, scales. This was ugly and bad and didn’t work in most cases, so I threw together some hacks to make it work,. geom_segment arrow direction. Without ggforce, this would require manually adding both the text and the arrow to the ggplot. 3 Visualize stars with geom_stars(). geom_arrow () is the same as geom_vector () but defaults to preserving the direction under coordinate transformation and different plot ratios. This geom draws genes as arrows along a horizontal line representing the molecule. The arrowheadr functions do not depend on ggarrow, but were designed to be used with ggarrow. I haven't used the ggraph package myself, but based on my understanding of the underlying grobs, you can try the following: Step 1. Source: R/geom-crossbar. library (ggplot2) df <- data. The placement of both the scale bar et north arrow are controlled by the location, pad_x and pad_y arguments of the annotation_scale() and annotation_north_arrow() functions from package ggspatial. the same binwidth, breaks, or bins). Date (c ("2015-03-01")), y = 448, xend =. 25, 0. Details. I'm trying to color code arrows based on their direction using geom_path in ggplot2. Current these replace only geom_segment() and work only for linear coordinate systems. R geom_rect-method. autoplot-method: Generic autoplot function geom_alignment-method: Alignment geoms for GRanges object geom_arch-method: Arch geoms for GRanges object geom_arrow-method: Arrow geoms for GRanges object geom_arrowrect-method:. Use “point” (to show only points); “text” to show only labels; c(“point”, “text”) or c(“arrow”,. geom_contour_fill() This geom has a bit of a long story. Before ggplot2 introduced geom_contour_filled(), the ‘canonical’ way to get filled contours was by using stat_contour() with a polygon geom and mapping fill to level (see this issue). 0. trying to draw an arrow with geom_segment. The labels argument is the one used to customize the labels, where you can input a vector with the new labels or a custom labeller function as in the example below. geom_arrow_segment() understands the following aesthetics (required aesthetics are in bold): x. geom_path() connects the observations in the order in which they appear in the data. Contribute to opendilab/DI-engine development by creating an account on GitHub. geom_segment (aes (x = as. g. geom_stars() from the stars package lets you use a stars object directly to easily create a map under the ggplot2 framework. Scale bar and North arrow (package ggspatial) Several packages are available to create a scale bar on a map (e. Parametrization of ggplot2::geom_segment either by location and displacement or by magnitude and angle with default arrows. addlabel: a logical value. Use coordinate data with coord_sf() geom_spatial_rect() geom_spatial_tile() StatSpatialRect StatSpatialTile. 5, arrow. linemitre: Line mitre limit (number greater than 1). geom_arrow() now is geom_vector() with better documentation and more parameters and geom_arrow() is a new geom for arrows that preserve direction. Before ggplot2 introduced geom_contour_filled(), the ‘canonical’ way to get filled contours was by using stat_contour() with a polygon geom and mapping fill to level (see this issue). Does. R layout_linear-method. See ggarrow’s arrow ornament vignette for more options. Often the orientation is easy to deduce from a combination of the given mappings and the types of positional scales in. 5, -. How can I add two-headed arrows (or brackets) in year 2030 on the plot to show the differences between emissions at year 2030 with emission levels of year 2005 (the black horizontal line). 函数曲线: geom_function、stat_function. you specified the start point ( x) as a date, while the end point ( xend) as a number. , xlab, ylab, main, angle. Here is an alternative approach using package 'ggpmisc'. Add supplementary data to a plotCreate a karyogram layout. ggalt. , start = 0, direction = c ("ccw", "cw"), pivot = 0. geom_contour_fill() This geom has a bit of a long story. Segments with geom_segment. , arrow = NULL, arrow. We saw above that geom_raster() requires converting a stars object to a data. They may also be parameters to the paired geom/stat. geom_arrow: Arrows; geom_contour2: 2d contours of a 3d surface; geom_contour_fill: Filled 2d contours of a 3d surface; geom_contour_tanaka: Illuminated contours; geom_relief: Relief Shading; geom_streamline: Streamlines; geom_text_contour: Label contours; geopotential: Geopotential height; GeostrophicWind: Calculate. "jitter" to use position_jitter), or the result of a call to a position. The reason for removal is that some values ARE missing (NA). scores %>% arrange (year) %>% #sort ascending so that 2018 is plotted last ggplot () + geom_point (aes (x = NMDS1, y =. geom_arrow () is the same as. names (. geom_rect() has aesthetics xmin, xmax, ymin and ymax. Again, the ‘canonical’ way of plotting vectors is to use geom_segment() and specify x, y, xend and yend aesthetics which can be a lot of typing when one has the data on location and displacement (or velocity). 示例 1. However, there are some occasions when it is useful to have text follow a curved path. Here is a sample code of gg_arrow: install. lineend. out and y. There’s another built-in ggplot labeling function called geom_label (), which is similar to geom_text () but adds a box around the text. #' @param linetype the linetype to be used when geom ="arrow" #' @param repel a boolean, whether to use ggrepel to avoid overplotting text #' labels or not. Line join style (round, mitre, bevel). If x is ggplot object, it first try to estimate current x limits and y limits of the ggplot object, then rescale based on those information. The upper geom_point layer draws points at the starting points of the line segments (filled in white, with a black outline). I'm trying to color code arrows based on their direction using geom_path in ggplot2. xmin, xmax, ymin and ymax can be used to specify the position of annotations and to represent rectangular areas. The data to be displayed in this layer. It doesn’t work well for contours that end at the edges. Line end style (round, butt, square). , curvature = 0. See the underlying drawing function grid::curveGrob () for the parameters that control the curve. They can be used by themselves as scatterplots or in combination with other geoms, for example, for labeling points or for annotating the height of bars. geom_arrow_segment () understands the following aesthetics (required aesthetics are in bold): The linewidth_fins and linewidth_head inherit from linewidth. wiki. It intelligently reads dimensions and data and returns a tidy data. If specified, overrides the default data frame defined at the top level of the plot. Rで描いた、いろいろなビジュアライゼーションを集めました。基本的には、ggplotで描いていますが、ggplotでの表現が煩雑に. fviz_pca_var (pca, title = "", repel = TRUE, #This is the only change I made parse = T, ggtheme = theme_bw ()) # Rest of your code. x = skip, skip. fill: fill color to use for the arrow head (if closed). ggplot - Labeling each line at the end using an arrow. I am currently reading R for Data Science by Hadley Wickham. Parametrization of ggplot2::geom_segment either by location and displacement or by magnitude and angle with default arrows. Description. shape = 22, filled square blue. Also the fact that the specified arrow position corresponds to the arrowhead tip can make lines look a little lopsided; it would be much. 3. A data. geom1 and d. ReadNetCDF() now handles more date formats. See fortify () for which variables will be created. Functions that return functions suitable to use as the breaks argument in ggplot2's continuous scales and in geom_contour_fill. Connect the observations in the order in which they appear in the data and then convert them with ggplotly. Does anyone know how to resolve this error? Thankstracks. geom_sf() is an unusual geom because it will draw different geometric objects depending on what simple features are present in the data: you can get points, lines, or polygons. gedit ("segments", gp=gpar (linejoin ='mitre')) # change the shape in legend also grid. geom_arrow: Arrows; geom_contour2: 2d contours of a 3d surface; geom_contour_fill: Filled 2d contours of a 3d surface; geom_contour_tanaka: Illuminated contours; geom_relief: Relief Shading; geom_streamline: Streamlines; geom_text_contour: Label contours; geopotential: Geopotential height; GeostrophicWind: Calculate. stl) in the xml (banana. geom_arrow; geom_callout; geom_chevron; geom_cross; geom_diamond; geom_elbow; geom_parallelogram; geom_pentagon; geom_triangle; Example. Unlike geom_ or stat_ functions, layer_spatial. Not very sure how you will use this in your plot because x is a factor, so I show an example below how the arrow works. 0. Before ggplot2 introduced geom_contour_filled(), the ‘canonical’ way to get filled contours was by using stat_contour() with a polygon geom and mapping fill to level (see this issue). MakeBreaks is essentially an export of the default way ggplot2::stat_contour makes breaks. First, we have to install and load the ggplot2 package: install. R layout_karyogram-method. Force of repulsion between overlapping text labels. arrow: specification for arrow heads, as created by grid::arrow(). Used as the axis or legend title. Standard 'ggplot2' aesthetics for text are supported (see. The statistical transformation to use on the data for this layer, either as a ggproto Geom subclass or as a string naming the stat stripped of the stat_ prefix (e. 以下がコードの主な部分で、viewerの add_marker でマーカーを追加すること. Again, the 'canonical' way of plotting vectors is to use geom_segment() and specify x , y , xend and yend aesthetics which can be a lot of typing when one has the data on location and displacement (or velocity). The curvature, angle and ncp arguments of geom_curve are also available: if curvature is set to any value above 0 (the default), the. Use stat_smooth () if you want. mag = 0, skip = 0,. na. This may be to create or recreate a specific visual effect, or. 11 ): The default angle is 30, and the default length of the arrowhead lines is 0. R geom_chevron-method. Database. This will. It doesn’t work well for contours that end at the edges. With the first option, you need to specify stat = "identity" for it to work, so the ladder is used throughout the article. These are often aesthetics, used to set an aesthetic to a fixed value, like colour = "red" or size = 3. geom_stars() works just like geom_sf(). Drawing gene arrows with geom_gene_arrow(). Legend keys will be drawn with the same aesthetics as the geom they relate to, which in this case is geom_arrow(). R stat_coverage-method. arrow_mid. ) The extended functionality is to allow free placement of the arrowhead anywhere along the segment, and also multiple arrowheads, and to allow a fill aesthetic (which will only be visible for closed arrowheads). R has a mathematical annotation system via plotmath, but I like the look of true equations better. Details. Vertical intervals: lines, crossbars & errorbars. )), aes (x = x, y = y, label = labs)) If you want the plot to be a little easier on the eyes and avoid plotting. Run this code. ggplot2 - annotate outside of plot. geom_text(data, x, y, label) Parameter: data: dataframe in consideration; x: x coordinate of text; y: y coordinate of text; label: text; To annotate using this function, first, a dataframe of the values is created and then the values to geom_title() are passed with reference to the dataframe so created. The package supports detailed views of particular. Try updating your browser and graphics drivers or restarting your computer. R layout_circle-method. For example, if you use geom "point", you need to provide "y" in aes(), and if can also pass color, fill, size etc. geom_arrow: Arrows; geom_contour2: 2d contours of a 3d surface; geom_contour_fill: Filled 2d contours of a 3d surface; geom_contour_tanaka: Illuminated contours; geom_relief: Relief Shading; geom_streamline: Streamlines; geom_text_contour: Label contours; geopotential: Geopotential height; GeostrophicWind: Calculate. Optionally, an additional forward aesthetic can be used to reverse the orientation of some. This geom treats each axis differently and, thus, can thus have two orientations. g. With ggplot2, shapes and line types can be assigned overall (e. We would like to show you a description here but the site won’t allow us. I made arrowheadr to facilitate getting complex shapes into the box that ggarrow functions expect. README ggarchery: Flexible segment geoms with arrows for ggplot2 ggarchery is intended to extend ggplot2 ’s handling of segments with arrowheads. We can use geom_cladelabel() to add another geom layer to annotate a selected clade with a bar indicating the clade with a corresponding label. Adding Arrows into ggplot. They can be used by themselves as scatterplots or in combination with other geoms, for example, for labeling points or for annotating the height of bars. force () # change shape of arrows grid. fill: fill colour to use for the arrow head (if closed). dir = TRUE, min. I am trying to make my graph look as good as possible. ExamplesIs there a way in geom_spoke() to get arrows to point to the direction of the given data? If I have data with a location (x,y) and an angle, it seems ideal to me to use geom_spoke, but I would expect to be able to choose in which direction the arrows should point (away from the coordinates or pointing to them; I want the latter). which_north: "grid" results in a north arrow always. If waiver(), the default, the name of the scale is taken from the first mapping used for that aesthetic. I would like to make the arrow halfway through the lines. 2) However, I actually want the "test" to appear at the bottom. Allowed values are the combination of c(“point”, “arrow”, “text”). R theme. This tutorial describes how to add one or more straight lines to a graph generated using R software and ggplot2 package. aes = TRUE) geom_curve (mapping = NULL, data = NULL, stat = "identity", position = "identity",. They may also be parameters to the paired geom/stat. Unlike geom_line(), which connects points in the order they appear along the x-axis, geom_path() connects points in the order they appear in the data. The geom_text and geom_label functions allows adding text or labels, respectively, to plots created with ggplot2. 3. For simple plots, you will only need geom_sf() as it uses stat_sf() and adds coord_sf() for you. If FALSE, the default, missing values are removed with a warning. As stat_peaks() finds the peak and builds the labels on-the-fly this code can be used together with facets or grouped data nearly unchanged. geom_arrow: Arrows; geom_contour2: 2d contours of a 3d surface; geom_contour_fill: Filled 2d contours of a 3d surface; geom_contour_tanaka: Illuminated contours; geom_relief: Relief Shading; geom_streamline: Streamlines; geom_text_contour: Label contours; geopotential: Geopotential height; GeostrophicWind: Calculate. The ggbio package extends and specializes the grammar of graphics for biological data. I illustrate my Problems: Create some sample data and a plot: geom_segment (mapping = NULL, data = NULL, stat = "identity", position = "identity",. And the text box should point the corresponding. Many geom_edge_* layers comes in 3 flavors depending on the level of control needed over the drawing. pdf document. geom_curve () draws a curved line. This course is a. (scratch. In this guide we are going to use the following example plot. Try the following. 5, preserve. This geom treats each axis differently and, thus, can thus have two orientations. R グラフィックス クックブック 20回目 ggplot2パッケージを利用して、図内に注釈を入れます。 注釈 データの解釈をサポートするために、図内に注釈を入れるのですが、 注釈自体は、いろいろあります。 テキスト(文字列、数式) 線(線分、矢印) 網掛け 強調 エラーバー これらを、1個ずつ. → Confidence Interval (CI). To install the development version use (make sure that devtools is installed):Connect observations, ordered by x value. geom_arrow: Arrows; geom_contour2: 2d contours of a 3d surface; geom_contour_fill: Filled 2d contours of a 3d surface; geom_contour_tanaka: Illuminated contours; geom_relief: Relief Shading; geom_streamline: Streamlines; geom_text_contour: Label contours; geopotential: Geopotential height; GeostrophicWind: Calculate geostrophic windsThe function ReadNetCDF () relies on the ncdf4 package to read NetCDF files with ease. Details. It is possible to change the font size for the legend of the scale bar (argument legend_size, which defaults to 3). Try updating your browser and graphics drivers or restarting your computer. The code below uses a statistic instead of annotate() making it more generally useful. GGPLOT -. Alternatively, a user # ' controllable arrow created with [`grid::arrow()`] can be used. 1. annotate hline in ggplot with arrow. The previous functions can be used to add lines to the plots, but you cannot create segments with them. geom_segment (mapping = NULL, data = NULL, stat = "identity", position = "identity",. Description. Using the waffle package, we will create waffle charts of Iron (Fe) groundwater contamination across 4 regions (West, Central, Midwest, and East) in the U. Now that we’ve quickly reviewed ggplot2 syntax, let’s take a look at how geom_line fits in. Nudging is built in to geom_text () because it's so useful for moving labels a small distance from what they're labelling. All core Bioconductor data structures are supported, where appropriate. These geoms act slightly differently from other geoms. fill: fill colour to use for the arrow head (if closed). Each point along the line has a numeric value associated with it giving the position along the path, and it is therefore possible to show. You can search and browse Bioconductor packages here. shape = 24, filled triangle point-up blue. Orientation. geom_contour_fill() In ggplot2, the ‘canonical’ way to get filled contours is by using stat_contour() with a polygon geom and mapping fill to level (see this issue), but this has three important limitations. rmDetails. GEOM 2010 and GEOM 3030 (GEOM 3030 may be taken concurrently, as a co-requisite) course outline. For that reason there exists the geom_segment function, which allows specifying the X and Y coordinates of the start and end of the desired segment with x, y (start) and xend, yend (end), respectively. geom_arrow: Arrows; geom_contour2: 2d contours of a 3d surface; geom_contour_fill: Filled 2d contours of a 3d surface; geom_contour_tanaka: Illuminated contours; geom_relief: Relief Shading; geom_streamline: Streamlines; geom_text_contour: Label contours; geopotential: Geopotential height; GeostrophicWind: Calculate. The tikzdevice package is great if you are generating a . geom_label_repel draws a rectangle underneath the text, making it easier to read. Using ggplot2, 2 main functions are available for that kind of annotation: . color, awt. Share Tweet. g. R geom_chevron-method. geom_arrow: Arrows; geom_contour2: 2d contours of a 3d surface; geom_contour_fill: Filled 2d contours of a 3d surface; geom_contour_tanaka: Illuminated contours; geom_relief: Relief Shading; geom_streamline: Streamlines; geom_text_contour: Label contours; geopotential: Geopotential height; GeostrophicWind: Calculate. "point" rather than "geom_point") kriging: Logical indicating whether to perform ordinary kriging before contouring. na. geom_text_repel adds text directly to the plot. This is useful for adding small annotations (such as text labels) or if you have your data in vectors, and. Also note that you can use the color, size, linetype, shape, and fill arguments to modify the appearance of both the line and the points in the plot:geom_contour_fill() This geom has a bit of a long story. R, R/stat-function. A bubblechart is a scatterplot with a third variable. . There are three options: If NULL, the default, the data is inherited from the plot data as specified in the call to ggplot (). ggplot () + geom_line (data=emissions. xml) in the asset region. The default (no numeric postfix) generate a number of points (n) along the edge and draws it as a path. Look of arrows in ggplot2 geom_segment() 3. Current these replace only geom_segment() and work only for linear coordinate systems. The main task is easily done with geom_line(arrow = arrow()). renderable. We would like to show you a description here but the site won’t allow us. This is my code: They may also be parameters to the paired geom/stat. ggplot2 is a powerful and a flexible R package, implemented by Hadley Wickham, for producing elegant graphics. This post will connect the dots, so to speak, by introducing the concept of edges. annotate (): useful for adding small text annotations at a particular location on the plot. The graphics are designed to answer common scientific questions, in particular those often asked of high throughput genomics data. segment[(; arrow=false, filled=false)] Draw line segments from `x`, `y` to `xend`, `yend`. But, with geom_mark it is a simple as setting the label argument. It would be much cleaner to line them up along the outside edge of the plot. frame, and will be used as the layer data. obj. You can draw outside the panel using the argument clip="off" in coord_cartesian. Related. ggplot - Labeling each line at the end using an arrow. It’s possible to add arrowheads or flat ends to the line segments, using arrow () from the grid package. 3. Limitations. ggtree is an R package that extends ggplot2 for visualizating and annotating phylogenetic trees with their covariates and other associated data. aes = TRUE). geom_path (), geom_line (), and geom_step () handle NA as follows: If an NA occurs in the middle of a line, it breaks the line. 1. arrow. I would like to associate sample size values with points on a plot. Aside from these, there is also geom_arrow_chain(), which has no equivalent in vanilla ggplot2. Arrow specification, as created by grid::arrow(). Added total amount of explained variance as a caption in the plot. A translation maps points R to R' at (-4,8). "point" rather than "geom_point") position. If you are not, then you might want to consider other options. arrow: specification for arrow heads, as created by arrow(). ; Geometries. Add arrow at the end of a `geom_segment` instead of. Before ggplot2 introduced geom_contour_filled(), the ‘canonical’ way to get filled contours was by using stat_contour() with a polygon geom and mapping fill to level (see this issue). Hi @mchiapello, sorry it took me a while to get to this issue. geom_stars() from the stars package lets you use a stars object directly to easily create a map under the ggplot2 framework. 线段和曲线: geom_segment、geom_spoke、geom_curve. Custom Arrowheads. 0. g. ggstance. 8. total, aes (x=year, y =Emissions, colour=Scenarios), linetype="dotted",show_guide = TRUE) + geom_line (data=emissions. R: ggplot2 pointrange example. dir = TRUE, min. arrow - (default: NULL) the arrow to draw at the end point of the line segment (use the arrow() function in R's grid package to create arrows) Example This plot contains two layers. The value of the maximum vector magnitude in scale_mag() is now chosen to be a “pretty” number close to the maximum. rmDescription. (It is assumed that the user wants some kind of arrow. "count" rather than "stat_count") arrow. Value. Add supplementary data to a plot. This was ugly and bad and didn’t work in most cases, so I threw together some hacks to make it work,. Geom. geom: geom plotted on the stacked layout. In this tutorial we are going to review the most common use cases of these functions. obj. geom_text_contour understands the following.