@lightningjs/renderer
Version:
Lightning 3 Renderer
69 lines • 2.51 kB
JavaScript
/*
* If not stated otherwise in this file or this component's LICENSE file the
* following copyright and licenses apply:
*
* Copyright 2025 Comcast Cable Communications Management, LLC.
*
* Licensed under the Apache License, Version 2.0 (the License);
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
import * as SdfFontHandler from '../SdfFontHandler.js';
/**
* Create a simple SDF font shaper
*/
export const createSdfFontShaper = () => ({
shapeText: function* (props, codepoints) {
// Host paths on top
const fontFamily = props.fontFamily;
const fontSize = props.fontSize;
const letterSpacing = props.letterSpacing;
const fontData = SdfFontHandler.getFontData(fontFamily);
if (fontData === null)
return;
const fontScale = fontSize / fontData.common.lineHeight;
let prevCodepoint = 0;
while (true) {
const result = codepoints.next();
if (result.done)
break;
const codepoint = result.value;
if (!codepoint)
continue;
// Get glyph data
const glyph = SdfFontHandler.getGlyph(fontFamily, codepoint);
if (glyph === null) {
yield {
mapped: false,
codepoint,
xAdvance: 0,
};
continue;
}
// Calculate advance with kerning
let advance = glyph.xadvance * fontScale;
// Add kerning if there's a previous character
if (prevCodepoint !== 0) {
const kerning = SdfFontHandler.getKerning(fontFamily, prevCodepoint, codepoint);
advance += kerning * fontScale;
}
// Add letter spacing
advance += letterSpacing;
yield {
mapped: true,
codepoint,
xAdvance: advance,
};
prevCodepoint = codepoint;
}
},
});
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