CanvasRenderingContext2D.textBaseline

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

CanvasRenderingContext2D.textBaseline - свойство Canvas 2D API, указывающее на текущую базовую линию при рисовании текста.

Синтаксис

ctx.textBaseline = "top" || "hanging" || "middle" || "alphabetic" || "ideographic" || "bottom";

Опции

Возможные значения:

"top"

The text baseline is the top of the em square.

"hanging"

The text baseline is the hanging baseline. (Used by Tibetan and other Indic scripts.)

"middle"

The text baseline is the middle of the em square.

"alphabetic"

The text baseline is the normal alphabetic baseline. Значение по умолчанию.

"ideographic"

The text baseline is the ideographic baseline; this is the bottom of the body of the characters, if the main body of characters protrudes beneath the alphabetic baseline. (Used by Chinese, Japanese, and Korean scripts.)

"bottom"

The text baseline is the bottom of the bounding box. This differs from the ideographic baseline in that the ideographic baseline doesn't consider descenders.

Примеры

Сравнение значений свойства

Этот пример демонстрирует различные значения свойства textBaseline и отображение линий при их применениях.

HTML

html
<canvas id="canvas" width="550" height="500"></canvas>

JavaScript

js
const canvas = document.getElementById("canvas");
const ctx = canvas.getContext("2d");

const baselines = [
  "top",
  "hanging",
  "middle",
  "alphabetic",
  "ideographic",
  "bottom",
];
ctx.font = "36px serif";
ctx.strokeStyle = "red";

baselines.forEach(function (baseline, index) {
  ctx.textBaseline = baseline;
  let y = 75 + index * 75;
  ctx.beginPath();
  ctx.moveTo(0, y + 0.5);
  ctx.lineTo(550, y + 0.5);
  ctx.stroke();
  ctx.fillText("Abcdefghijklmnop (" + baseline + ")", 0, y);
});

Результат

Спецификации

Specification
HTML Standard
# dom-context-2d-textbaseline-dev

Совместимость с браузерами

BCD tables only load in the browser

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