private void bumpPosition() {
		/* Bump the current X position */
		++xCur;

		/* If we are at the end of a scan line, set xCur back to the beginning */
		/* If we are interlaced, bump the yCur to the appropriate spot, */
		/* otherwise, just increment it. */
		if (xCur == imgW) {
			xCur = 0;

			if (!wantInterlaced)
				++yCur;
			else
				switch (curPass) {
				case 0:
					yCur += 8;
					if (yCur >= imgH) {
						++curPass;
						yCur = 4;
					}
					break;
				case 1:
					yCur += 8;
					if (yCur >= imgH) {
						++curPass;
						yCur = 2;
					}
					break;
				case 2:
					yCur += 4;
					if (yCur >= imgH) {
						++curPass;
						yCur = 1;
					}
					break;
				case 3:
					yCur += 2;
					break;
				}
		}
	}