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draw_text

draw_text

Mojo function šŸ”­

draw_text

fn def draw_text(mut canvas: Canvas, x: Int, y: Int, text: String, color: Color, size: Float64, family: String = "Sans", slant: FontSlant = FontSlant.NORMAL, weight: FontWeight = FontWeight.NORMAL, rotation: Float64 = 0, align: TextAlign = TextAlign.LEFT, kerning: Bool = True, ligatures: Bool = True)

Render text (one or more “\n”-separated lines) anchored at (x, y) in family at size points, compositing onto canvas in color. AA coverage combines with color.a through the same set_pixel() blend every other filled shape uses.

rotation (radians) rotates the whole block – every line together – around the (x, y) anchor. Transform2D’s rotation (geometry.mojo) instead tilts a whole data-to-pixel mapping.

Builds a FontCache per call and throws it away, so every call rescans every font file installed on the machine. That scan is tens of milliseconds where a cached label is tens of microseconds, and it does not shrink with the length of the string – a chart labeling its axes through this overload spends nearly all of its time in font discovery. Construct one FontCache and pass it to the cache= overload below for anything past a couple of strings.

Args:

  • canvas (Canvas): Canvas to draw into.
  • x (Int): Anchor x – baseline left end for LEFT alignment.
  • y (Int): Anchor y – baseline.
  • text (String): Text to draw, “\n”-separated lines.
  • color (Color): Text color.
  • size (Float64): Font size in points.
  • family (String): Font family name or generic alias.
  • slant (FontSlant): Requested upright/italic/oblique style.
  • weight (FontWeight): Requested normal/bold weight.
  • rotation (Float64): Radians, rotating the whole block around the anchor.
  • align (TextAlign): Horizontal alignment of each line.
  • kerning (Bool): Apply the font’s pair kerning between adjacent glyphs.
  • ligatures (Bool): Apply the font’s GSUB shaping – ligatures and Arabic contextual forms. False lays out one glyph per character.

Raises:

fn def draw_text(mut canvas: Canvas, x: Int, y: Int, text: String, color: Color, size: Float64, family: String = "Sans", slant: FontSlant = FontSlant.NORMAL, weight: FontWeight = FontWeight.NORMAL, rotation: Float64 = 0, align: TextAlign = TextAlign.LEFT, kerning: Bool = True, ligatures: Bool = True, *, mut cache: FontCache)

Like draw_text above, but resolving fonts through cache rather than fresh every call. Whole-pixel anchor; delegates to the sub-pixel overload below.

Args:

  • canvas (Canvas): Canvas to draw into.
  • x (Int): Anchor x – baseline left end for LEFT alignment.
  • y (Int): Anchor y – baseline.
  • text (String): Text to draw, “\n”-separated lines.
  • color (Color): Text color.
  • size (Float64): Font size in points.
  • family (String): Font family name or generic alias.
  • slant (FontSlant): Requested upright/italic/oblique style.
  • weight (FontWeight): Requested normal/bold weight.
  • rotation (Float64): Radians, rotating the whole block around the anchor.
  • align (TextAlign): Horizontal alignment of each line.
  • kerning (Bool): Apply the font’s pair kerning between adjacent glyphs.
  • ligatures (Bool): Apply the font’s GSUB shaping – ligatures and Arabic contextual forms. False lays out one glyph per character.
  • cache (FontCache): Shared cache for font resolution and parsed faces.

Raises:

fn def draw_text(mut canvas: Canvas, x: Float64, y: Float64, text: String, color: Color, size: Float64, family: String = "Sans", slant: FontSlant = FontSlant.NORMAL, weight: FontWeight = FontWeight.NORMAL, rotation: Float64 = 0, align: TextAlign = TextAlign.LEFT, kerning: Bool = True, ligatures: Bool = True)

Draw text at a sub-pixel anchor, resolving fonts for this call.

Args:

  • canvas (Canvas): Canvas to draw into.
  • x (Float64): Anchor x, sub-pixel – baseline left end for LEFT alignment.
  • y (Float64): Anchor y, sub-pixel – baseline.
  • text (String): Text to draw, “\n”-separated lines.
  • color (Color): Text color.
  • size (Float64): Font size in points.
  • family (String): Font family name or generic alias.
  • slant (FontSlant): Requested upright/italic/oblique style.
  • weight (FontWeight): Requested normal/bold weight.
  • rotation (Float64): Radians, rotating the whole block around the anchor.
  • align (TextAlign): Horizontal alignment of each line.
  • kerning (Bool): Apply the font’s pair kerning between adjacent glyphs.
  • ligatures (Bool): Apply the font’s GSUB shaping – ligatures and Arabic contextual forms. False lays out one glyph per character.

Raises:

fn def draw_text(mut canvas: Canvas, x: Float64, y: Float64, text: String, color: Color, size: Float64, family: String = "Sans", slant: FontSlant = FontSlant.NORMAL, weight: FontWeight = FontWeight.NORMAL, rotation: Float64 = 0, align: TextAlign = TextAlign.LEFT, kerning: Bool = True, ligatures: Bool = True, *, mut cache: FontCache)

Draw text at a sub-pixel anchor using cache for font resolution.

A sub-pixel anchor places a label against something itself at a fractional position – a tick at x = 103.7, a label centered on a bar whose midpoint is not a whole pixel. Rounding the anchor first shifts the whole string.

Args:

  • canvas (Canvas): Canvas to draw into.
  • x (Float64): Anchor x – baseline left end for LEFT alignment.
  • y (Float64): Anchor y – baseline.
  • text (String): Text to draw, “\n”-separated lines.
  • color (Color): Text color.
  • size (Float64): Font size in points.
  • family (String): Font family name or generic alias.
  • slant (FontSlant): Requested upright/italic/oblique style.
  • weight (FontWeight): Requested normal/bold weight.
  • rotation (Float64): Radians, rotating the whole block around the anchor.
  • align (TextAlign): Horizontal alignment of each line.
  • kerning (Bool): Apply the font’s pair kerning between adjacent glyphs.
  • ligatures (Bool): Apply the font’s GSUB shaping – ligatures and Arabic contextual forms. False lays out one glyph per character.
  • cache (FontCache): Shared cache for font resolution and parsed faces.

Raises:

draw_layoutdraw_text_on_path