A method of picture coding implemented by a decoding device or an encoding device, the method comprising: obtaining a value of an angle parameter for a current block, a value of a distance index, a value of a width of the current block and a value of a height of the current block, calculating a ratio value between the values of the width and the height of the current block, and obtaining a first value according to the value of the angle parameter and the ratio value, the first value being obtained using a lookup table, wherein the value of the angle parameter and the ratio value are used as an index value for the lookup table; wherein the first value represents a linearly scaled distance step size and the ratio value represents a ratio between the width of the current block and the height of the current block, and wherein the angle parameter and the distance index describe a separation line for dividing the current block into two subblocks; calculating a sample distance value for a sample in the current block according to the first value, the value of the angle parameter, the value of the distance index and the value of the width and the value of the height; and obtaining a prediction value for the sample in the current block according to the sample distance value, wherein the sample distance value represents the horizontal distance or the vertical distance, or a combination of the vertical and horizontal distance, of the sample to a separation line, and wherein the obtaining a prediction value for the sample in the current block according to the sample distance value comprises: calculating two weighting factors according to the sample distance value; obtaining the prediction value for the sample in the current block according to a first prediction value, a second prediction value and the two weighting factors. obtaining a value of an angle parameter for a current block, a value of a distance index, a value of a width of the current block and a value of a height of the current block, calculating a ratio value between the values of the width and the height of the current block, and obtaining a first value according to the value of the angle parameter and the ratio value, the first value being obtained using a lookup table, wherein the value of the angle parameter and the ratio value are used as an index value for the lookup table; wherein the first value represents a linearly scaled distance step size and the ratio value represents a ratio between the width of the current block and the height of the current block, and wherein the angle parameter and the distance index describe a separation line for dividing the current block into two subblocks; calculating a sample distance value for a sample in the current block according to the first value, the value of the angle parameter, the value of the distance index and the value of the width and the value of the height; and obtaining a prediction value for the sample in the current block according to the sample distance value, wherein the sample distance value represents the horizontal distance or the vertical distance, or a combination of the vertical and horizontal distance, of the sample to a separation line, and wherein the obtaining a prediction value for the sample in the current block according to the sample distance value comprises: calculating two weighting factors according to the sample distance value; obtaining the prediction value for the sample in the current block according to a first prediction value, a second prediction value and the two weighting factors. calculating two weighting factors according to the sample distance value; obtaining the prediction value for the sample in the current block according to a first prediction value, a second prediction value and the two weighting factors.