BlenderRenderController.MainForm.prevChunkButton_Click C# (CSharp) Method

        private void prevChunkButton_Click(object sender, EventArgs e)
        {
            var difference = endFrameNumericUpDown.Value - startFrameNumericUpDown.Value;

            if (startFrameNumericUpDown.Value - difference < 1)
            {
                startFrameNumericUpDown.Value = 1;
                endFrameNumericUpDown.Value = 1 + difference;
            }
            else
            {
                endFrameNumericUpDown.Value = startFrameNumericUpDown.Value - 1;
                startFrameNumericUpDown.Value = endFrameNumericUpDown.Value - difference;
            }

        }