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 июль 2015 г..
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
<canvas id="canvas" width="550" height="500"></canvas>
JavaScript
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> # dom-context-2d-textbaseline-dev> |
Совместимость с браузерами
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Смотрите также
- Интерфейс определяющий это свойство:
CanvasRenderingContext2D