feat(pixel): update getRegion() return type

BREAKING CHANGE: update getRegion() to return undefined
if result region < 1 pixel

- add size checks to impls in IntBuffer/FloatBuffer

packages/pixel/src/api.ts

@@ -233,7 +233,7 @@ export interface IPixelBuffer<T extends TypedArray = TypedArray, P = any>
 		y: number,
 		width: number,
 		height: number
-	): IPixelBuffer<T, P>;
+	): IPixelBuffer<T, P> | undefined;
 }
 
 export interface IBlit<T extends IPixelBuffer> {

packages/pixel/src/float.ts

@@ -375,6 +375,7 @@ export class FloatBuffer
 			this.width,
 			this.height
 		);
+		if (w < 1 || h < 1) return;
 		return this.blit(new FloatBuffer(w, h, this.format), {
 			sx,
 			sy,

packages/pixel/src/int.ts

@@ -178,8 +178,8 @@ export class IntBuffer
 		return 2;
 	}
 
-	as(fmt: IntFormat) {
-		return this.getRegion(0, 0, this.width, this.height, fmt);
+	as(fmt: IntFormat): IntBuffer {
+		return this.getRegion(0, 0, this.width, this.height, fmt)!;
 	}
 
 	copy() {
@@ -326,6 +326,7 @@ export class IntBuffer
 			this.width,
 			this.height
 		);
+		if (w < 1 || h < 1) return;
 		return this.blit(new IntBuffer(w, h, fmt || this.format), {
 			sx,
 			sy,