DialogReader.readOptions throws exception

[crispyross]

I'm trying to write a new version of the transcript app that can keep track of multiple dialogue trees and that formats everything according to the RS wiki's formatting. I ran into this exception when trying to call DialogReader.read(). I'm not sure if I'm using the API wrong, or if this is an issue in the API.

Uncaught Error: System.InvalidOperationException: Could not execute method: bindGetRegion(1, -537, -693, 500, 1)  ---> System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.ArgumentOutOfRangeException: Non-negative number required.
Parameter name: srcOffset
   at System.Buffer.BlockCopy(Array src, Int32 srcOffset, Array dst, Int32 dstOffset, Int32 count)
   at Runeapps.Alt1.ImageBuffer.Clone(Rectangle rect)
   at Runeapps.Alt1.BoundObject.Alt1BoundObject.bindGetRegion(Int32 id, Int32 x, Int32 y, Int32 w, Int32 h)
   --- End of inner exception stack trace ---
   at System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor)
   at System.Reflection.RuntimeMethodInfo.UnsafeInvokeInternal(Object obj, Object[] parameters, Object[] arguments)
   at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
   at System.Reflection.MethodBase.Invoke(Object obj, Object[] parameters)
   at CefSharp.Internals.JavascriptObjectRepository.TryCallMethod(Int64 objectId, String name, Object[] parameters, Object& result, String& exception)
   --- End of inner exception stack trace ---
   at CefSharp.Internals.JavascriptObjectRepository.TryCallMethod(Int64 objectId, String name, Object[] parameters, Object& result, String& exception)
    at transferImageData (webpack-internal:///../node_modules/@alt1/base/wrapper.ts:189:22)
    at ImgRefBind.read (webpack-internal:///../node_modules/@alt1/base/imgref.ts:67:80)
    at ImgRefBind.toData (webpack-internal:///../node_modules/@alt1/base/imgref.ts:29:21)
    at DialogReader.readOptions (webpack-internal:///../node_modules/@alt1/dialog/index.ts:196:36)
    at DialogReader.read (webpack-internal:///../node_modules/@alt1/dialog/index.ts:87:31)
    at readDialog (webpack-internal:///./Dialog.ts:10:25)
    at update (webpack-internal:///./index.ts:53:75)

The line that causes the exception appears to be the following:

var checkline = imgref.toData(dx, dy, Math.min(500, imgref.width - a), 1);

Here are the local variables at that line:

Here are the relevant parts of my code:

function update() {
	// .....
	let pos;
	try {
		pos = reader.find();
	}
	catch (e) {
		debugHtml.innerText += "reader.find failed: " + JSON.stringify(e) + '\n';
		return;
	}
	if (!pos) {
		debugHtml.innerText += "reader.find failed\n";
		return;
	}

	const dlg = readDialog(reader);
	// ....
}

// .....

function readDialog(reader: DialogReader): TextDialog|OptionsDialog|null {
    const read = reader.read();
    if (read === null || read === false)
        return null;
    if (read.text)
        return {
            title: toTitleCase(read.title),
            text: read.text.join(" ")
        };
    else
        return {
            title: toTitleCase(read.title),
            options: read.opts.map((opt, i) => ({
                text: opt.text,
                index: i
            }))
        }
}

I have also tried calling find by passing in an ImageRef, with the same result:

		const img = a1.captureHoldFullRs();
		pos = reader.find(img);

[skillbert]

The stack you pasted is caused by trying to read pixels outside of the captured area. I haven't gone through all of your code so i don't know why. I believe the meg solver is the only app right now that uses this code so you could look at how that works.

[crispyross]

Thank you. The issue turned to be that DialogReader.read sets a default for img (via ensureimg) if you don't pass in an ImageRef, which wasn't the expected dimensions. If I explicitly pass in the ImageRef I got from captureHoldFullRs, then it works.