feat(mermaid): display an error when PNG export could not occur

This commit is contained in:
Elian Doran
2025-03-31 18:36:57 +03:00
parent f3b866fa7b
commit 3cdbc76fff
3 changed files with 56 additions and 33 deletions

View File

@@ -650,47 +650,58 @@ function triggerDownload(fileName: string, dataUrl: string) {
*
* @param nameWithoutExtension the name of the file. The .png suffix is automatically added to it.
* @param svgContent the content of the SVG file download.
* @returns `true` if the operation succeeded (width/height present), or `false` if the download was not triggered.
* @returns a promise which resolves if the operation was successful, or rejects if it failed (permissions issue or some other issue).
*/
function downloadSvgAsPng(nameWithoutExtension: string, svgContent: string) {
const mime = "image/svg+xml";
return new Promise<void>((resolve, reject) => {
const mime = "image/svg+xml";
// First, we need to determine the width and the height from the input SVG.
const svgDocument = (new DOMParser()).parseFromString(svgContent, mime);
const width = svgDocument.documentElement?.getAttribute("width");
const height = svgDocument.documentElement?.getAttribute("height");
// First, we need to determine the width and the height from the input SVG.
const svgDocument = (new DOMParser()).parseFromString(svgContent, mime);
const width = svgDocument.documentElement?.getAttribute("width");
const height = svgDocument.documentElement?.getAttribute("height");
if (!width || !height) {
return false;
}
if (!width || !height) {
reject();
return;
}
// Convert the image to a blob.
const svgBlob = new Blob([ svgContent ], {
type: mime
})
// Convert the image to a blob.
const svgBlob = new Blob([ svgContent ], {
type: mime
})
// Create an image element and load the SVG.
const imageEl = new Image();
imageEl.width = parseFloat(width);
imageEl.height = parseFloat(height);
imageEl.src = URL.createObjectURL(svgBlob);
imageEl.onload = () => {
// Draw the image with a canvas.
const canvasEl = document.createElement("canvas");
canvasEl.width = imageEl.width;
canvasEl.height = imageEl.height;
document.body.appendChild(canvasEl);
// Create an image element and load the SVG.
const imageEl = new Image();
imageEl.width = parseFloat(width);
imageEl.height = parseFloat(height);
imageEl.onload = () => {
try {
// Draw the image with a canvas.
const canvasEl = document.createElement("canvas");
canvasEl.width = imageEl.width;
canvasEl.height = imageEl.height;
document.body.appendChild(canvasEl);
const ctx = canvasEl.getContext("2d");
ctx?.drawImage(imageEl, 0, 0);
URL.revokeObjectURL(imageEl.src);
const ctx = canvasEl.getContext("2d");
if (!ctx) {
reject();
}
const imgUri = canvasEl.toDataURL("image/png")
triggerDownload(`${nameWithoutExtension}.png`, imgUri);
document.body.removeChild(canvasEl);
};
ctx?.drawImage(imageEl, 0, 0);
URL.revokeObjectURL(imageEl.src);
return true;
const imgUri = canvasEl.toDataURL("image/png")
triggerDownload(`${nameWithoutExtension}.png`, imgUri);
document.body.removeChild(canvasEl);
resolve();
} catch (e) {
console.warn(e);
reject();
}
};
imageEl.src = URL.createObjectURL(svgBlob);
});
}
/**