chromium/third_party/blink/renderer/core/html/canvas/text_metrics.idl

/*
 * Copyright (C) 2008 Apple Inc. All Rights Reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

// https://html.spec.whatwg.org/C/#textmetrics

[Exposed=(Window,Worker)]
interface TextMetrics {
    // x-direction
    readonly attribute double width; // advance width
    readonly attribute double actualBoundingBoxLeft;
    readonly attribute double actualBoundingBoxRight;

    // y-direction
    readonly attribute double fontBoundingBoxAscent;
    readonly attribute double fontBoundingBoxDescent;
    readonly attribute double actualBoundingBoxAscent;
    readonly attribute double actualBoundingBoxDescent;
  [RuntimeEnabled=TextMetricsBaselines, MeasureAs="WebDXFeature::kCanvasTextBaselines"] readonly attribute double hangingBaseline;
    [RuntimeEnabled=TextMetricsBaselines, MeasureAs="WebDXFeature::kCanvasTextBaselines"] readonly attribute double alphabeticBaseline;
    [RuntimeEnabled=TextMetricsBaselines, MeasureAs="WebDXFeature::kCanvasTextBaselines"] readonly attribute double ideographicBaseline;
    [RuntimeEnabled=ExtendedTextMetrics] readonly attribute double emHeightAscent;
    [RuntimeEnabled=ExtendedTextMetrics] readonly attribute double emHeightDescent;

    // For editing, to get the text offset at a point
    [RuntimeEnabled=ExtendedTextMetrics] unsigned long caretPositionFromPoint(double x);

    // For selection
    [RuntimeEnabled=ExtendedTextMetrics, RaisesException] sequence<DOMRectReadOnly> getSelectionRects([EnforceRange] unsigned long start, [EnforceRange] unsigned long end);
    // For bounding box
    [RuntimeEnabled=ExtendedTextMetrics, RaisesException] DOMRectReadOnly getActualBoundingBox([EnforceRange] unsigned long start, [EnforceRange] unsigned long end);
};