Init

xcursor.js

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+'use strict';
+
+import GdkPixbuf from 'gi://GdkPixbuf';
+import Gio from 'gi://Gio';
+import GLib from 'gi://GLib';
+
+const XCURSOR_MAGIC = 0x72756358;
+const XCURSOR_IMAGE_TYPE = 0xfffd0002;
+
+function findCursorDir(theme) {
+    const paths = [
+        `${GLib.get_home_dir()}/.local/share/icons/${theme}/cursors`,
+        `${GLib.get_home_dir()}/.icons/${theme}/cursors`,
+        `/usr/share/icons/${theme}/cursors`,
+        `/usr/local/share/icons/${theme}/cursors`,
+    ];
+
+    for (const p of paths) {
+        if (GLib.file_test(p, GLib.FileTest.IS_DIR))
+            return p;
+    }
+
+    if (theme !== 'default' && theme !== 'Adwaita') {
+        for (const fallback of ['Adwaita', 'default']) {
+            const dir = findCursorDir(fallback);
+            if (dir) return dir;
+        }
+    }
+
+    return null;
+}
+
+function parseXcursor(filePath, targetSize) {
+    const file = Gio.File.new_for_path(filePath);
+    if (!file.query_exists(null))
+        return null;
+
+    let bytes;
+    try {
+        const [ok, contents] = file.load_contents(null);
+        if (!ok) return null;
+        bytes = contents;
+    } catch {
+        return null;
+    }
+
+    if (bytes.length < 16)
+        return null;
+
+    const view = new DataView(bytes.buffer, bytes.byteOffset, bytes.byteLength);
+
+    const magic = view.getUint32(0, true);
+    if (magic !== XCURSOR_MAGIC)
+        return null;
+
+    const headerSize = view.getUint32(4, true);
+    const ntoc = view.getUint32(12, true);
+
+    const images = [];
+    for (let i = 0; i < ntoc; i++) {
+        const tocOffset = headerSize + i * 12;
+        if (tocOffset + 12 > bytes.length) break;
+
+        const type = view.getUint32(tocOffset, true);
+        const nominalSize = view.getUint32(tocOffset + 4, true);
+        const filePos = view.getUint32(tocOffset + 8, true);
+
+        if (type === XCURSOR_IMAGE_TYPE)
+            images.push({nominalSize, filePos});
+    }
+
+    if (images.length === 0)
+        return null;
+
+    let best = images[0];
+    let bestDiff = Math.abs(best.nominalSize - targetSize);
+    for (let i = 1; i < images.length; i++) {
+        const diff = Math.abs(images[i].nominalSize - targetSize);
+        if (diff < bestDiff || (diff === bestDiff && images[i].nominalSize > best.nominalSize)) {
+            best = images[i];
+            bestDiff = diff;
+        }
+    }
+
+    const pos = best.filePos;
+    if (pos + 36 > bytes.length)
+        return null;
+
+    const width = view.getUint32(pos + 16, true);
+    const height = view.getUint32(pos + 20, true);
+    const xhot = view.getUint32(pos + 24, true);
+    const yhot = view.getUint32(pos + 28, true);
+
+    const pixelDataOffset = pos + 36;
+    const pixelDataSize = width * height * 4;
+    if (pixelDataOffset + pixelDataSize > bytes.length)
+        return null;
+
+    const pixels = new Uint8Array(bytes.buffer, bytes.byteOffset + pixelDataOffset, pixelDataSize);
+    return {width, height, xhot, yhot, pixels: new Uint8Array(pixels)};
+}
+
+// Colorize: tint * luminance (ARGB32 LE premultiplied, in-memory BGRA)
+function tintPixels(pixels, colorHex) {
+    const tr = parseInt(colorHex.slice(1, 3), 16);
+    const tg = parseInt(colorHex.slice(3, 5), 16);
+    const tb = parseInt(colorHex.slice(5, 7), 16);
+
+    const out = new Uint8Array(pixels.length);
+    for (let i = 0; i < pixels.length; i += 4) {
+        const a = pixels[i + 3];
+        if (a === 0)
+            continue;
+        const srcR = pixels[i + 2] * 255 / a;
+        const srcG = pixels[i + 1] * 255 / a;
+        const srcB = pixels[i + 0] * 255 / a;
+        const lum = (0.299 * srcR + 0.587 * srcG + 0.114 * srcB) / 255;
+        out[i + 0] = Math.round(tb * lum * a / 255);
+        out[i + 1] = Math.round(tg * lum * a / 255);
+        out[i + 2] = Math.round(tr * lum * a / 255);
+        out[i + 3] = a;
+    }
+    return out;
+}
+
+const CURSOR_NAMES = {
+    'default': ['default', 'left_ptr'],
+    'context-menu': ['context-menu', 'left_ptr'],
+    'help': ['help', 'left_ptr'],
+    'pointer': ['pointer', 'hand2'],
+    'progress': ['progress', 'left_ptr_watch'],
+    'wait': ['wait', 'watch'],
+    'cell': ['cell', 'plus'],
+    'crosshair': ['crosshair', 'cross'],
+    'text': ['text', 'xterm'],
+    'vertical-text': ['vertical-text'],
+    'alias': ['alias'],
+    'copy': ['copy'],
+    'move': ['move', 'fleur'],
+    'no-drop': ['no-drop'],
+    'not-allowed': ['not-allowed'],
+    'grab': ['grab', 'hand1'],
+    'grabbing': ['grabbing'],
+    'e-resize': ['e-resize', 'right_side'],
+    'n-resize': ['n-resize', 'top_side'],
+    'ne-resize': ['ne-resize', 'top_right_corner'],
+    'nw-resize': ['nw-resize', 'top_left_corner'],
+    's-resize': ['s-resize', 'bottom_side'],
+    'se-resize': ['se-resize', 'bottom_right_corner'],
+    'sw-resize': ['sw-resize', 'bottom_left_corner'],
+    'w-resize': ['w-resize', 'left_side'],
+    'ew-resize': ['ew-resize', 'sb_h_double_arrow'],
+    'ns-resize': ['ns-resize', 'sb_v_double_arrow'],
+    'nesw-resize': ['nesw-resize'],
+    'nwse-resize': ['nwse-resize'],
+    'col-resize': ['col-resize', 'sb_h_double_arrow'],
+    'row-resize': ['row-resize', 'sb_v_double_arrow'],
+    'all-scroll': ['all-scroll', 'fleur'],
+    'zoom-in': ['zoom-in'],
+    'zoom-out': ['zoom-out'],
+};
+
+// ARGB32 premultiplied LE (BGRA) -> RGBA straight alpha
+function argbPreToRgba(pixels, width, height) {
+    const rgba = new Uint8Array(width * height * 4);
+    for (let i = 0; i < width * height; i++) {
+        const si = i * 4;
+        const a = pixels[si + 3];
+        if (a === 0) continue;
+        rgba[si + 0] = Math.min(255, Math.round(pixels[si + 2] * 255 / a));
+        rgba[si + 1] = Math.min(255, Math.round(pixels[si + 1] * 255 / a));
+        rgba[si + 2] = Math.min(255, Math.round(pixels[si + 0] * 255 / a));
+        rgba[si + 3] = a;
+    }
+    return rgba;
+}
+
+function getCacheDir() {
+    const dir = `${GLib.get_user_cache_dir()}/cursor-overlay`;
+    if (!GLib.file_test(dir, GLib.FileTest.IS_DIR))
+        GLib.mkdir_with_parents(dir, 0o755);
+    return dir;
+}
+
+export function loadCursorPng(cursorDir, cursorName, targetSize, colorHex) {
+    const cacheDir = getCacheDir();
+    const cacheKey = `${cursorName}_${colorHex.replace('#', '')}_${targetSize}.png`;
+    const cachePath = `${cacheDir}/${cacheKey}`;
+
+    const names = CURSOR_NAMES[cursorName] || [cursorName, 'default', 'left_ptr'];
+
+    let parsed = null;
+    for (const name of names) {
+        parsed = parseXcursor(`${cursorDir}/${name}`, targetSize);
+        if (parsed) break;
+    }
+
+    if (!parsed)
+        return null;
+
+    if (!GLib.file_test(cachePath, GLib.FileTest.EXISTS)) {
+        const tinted = tintPixels(parsed.pixels, colorHex);
+        const rgba = argbPreToRgba(tinted, parsed.width, parsed.height);
+
+        try {
+            const pixbuf = GdkPixbuf.Pixbuf.new_from_bytes(
+                GLib.Bytes.new(rgba),
+                GdkPixbuf.Colorspace.RGB, true, 8,
+                parsed.width, parsed.height, parsed.width * 4
+            );
+            pixbuf.savev(cachePath, 'png', [], []);
+        } catch {
+            return null;
+        }
+    }
+
+    return {
+        path: cachePath,
+        xhot: parsed.xhot,
+        yhot: parsed.yhot,
+        width: parsed.width,
+        height: parsed.height,
+    };
+}
+
+export function getCursorTheme() {
+    const s = new Gio.Settings({schema_id: 'org.gnome.desktop.interface'});
+    return {theme: s.get_string('cursor-theme'), size: s.get_int('cursor-size')};
+}
+
+export {findCursorDir};