text.h File Reference

Text labels — the TextLayer. More...

#include <scimesh/font.h>
#include <scimesh/image.h>
#include <scimesh/types.h>
#include <algorithm>
#include <string>
#include <vector>

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Classes
struct	scimesh::TextDrawStyle
	How to draw text onto an image with draw_text(). More...
struct	scimesh::TextExtent
	Size of a (possibly multi-line) piece of text. More...
struct	scimesh::TextLayer
	A batch of text labels drawn together, in one coordinate space. More...
struct	scimesh::TextNodeRef
	A non-owning reference to one text layer in a scene, together with its placement transform (and optional name). More...

Namespaces
namespace	scimesh
namespace	scimesh::detail
	Internal helpers of the text renderer.

Enumerations
enum class	scimesh::TextSpace { scimesh::WORLD , scimesh::SCREEN }
	The coordinate space of a TextLayer's positions. More...

Functions
TextExtent	scimesh::measure_text (const std::string &text, float size, const std::string &font_file="", float line_spacing=1.2f)
	Measure a (possibly multi-line) string in a given font and size.
void	scimesh::draw_text (Image &image, const std::string &text, const Font &font, float x, float baseline_y, const TextDrawStyle &style=TextDrawStyle())
	Draw text into an image at a given position and baseline.
void	scimesh::detail::render_text_layers (const std::vector< TextNodeRef > &layers, Image &output, const Mat4 &view_projection, float pixel_scale, const std::vector< float > &z_buffer, const Color &default_color)
	Draw all text layers into an already rendered image.

Detailed Description

Text labels — the TextLayer.

Text layers are the third kind of screen-oriented primitive in scimesh, next to line layers (see lines.h) and meshes: they belong to a Scene, are drawn after the meshes and lines, and are ignored by the bounding box and by the mesh exporters, so adding labels never changes the camera framing.

A text layer is a list of strings with positions. Positions are either world space (projected with the scene camera, so a label sticks to the 3D point it annotates — good for "this sulcus", "this atom") or screen space (fixed output pixels — good for figure titles and axis labels). Labels are drawn as billboards, i.e. they always face the camera and keep their physical size; they are not 3D geometry, which is what makes them stay readable from any viewpoint.

The font comes from a .ttf file (see font.h); by default the bundled Inter-Regular.ttf is used. Glyphs are rasterized with anti-aliasing at the supersampled resolution, so labels are crisp and stay the same physical size when RenderOptions::aa_samples is raised.

Example

TextLayer labels;
labels.strings = {"anterior", "posterior"};
labels.positions = {Vec3(0, 1, 0), Vec3(0, -1, 0)};
labels.size = 18.0f;                       // output pixels
labels.color = Color(0, 0, 0, 1);          // (or use `colors` per label)
labels.adj = Vec2(0.5f, 0.5f);             // centred on the position
scene.add_texts(labels);

See also

Font, draw_text(), Scene::add_texts()

Definition in file text.h.