为了在移动设备上实现纹理合成，首先在总结了PC平台上纹理合成技术特点的基础上，指出基于Wang tiles的纹理合成适合在资源受限的移动平台上实现；然后通过深入分析Cohen随机贴片算法中的不足，提出了改进的基于Wang tiles的双向纹理合成新算法，即包括样本纹理子图的选取、片填充和基于双向扫描的贴片算法。该算法不仅扩大了最佳切割线的搜索范围和增加了贴片的随机性，同时也减少了计算和存储需求。实验结果表明，该算法不仅能够运行在移动设备上，而且与随机贴片算法相比，还提高了非周期性视觉效果。

Characteristics of current texture synthesis techniques on PC platform are summarized. Texture synthesis based on Wang tiles is suitable to be implemented on resource-constraint mobile devices. An improved bi-directional texture synthesis algorithm based on Wang tiles is presented through analyzing the stochastic tilling algorithm suggested by Cohen. The proposed algorithm mainly consists of the following steps: selecting sample sub-images, filling the tile with texture and tiling through bi-direction scanning. Accordingly, the search region for the best cut path is enlarged, randomicity of the selected tiles is increased and the requirements of computation and storage are also reduced. Experiments validate the usability of our algorithm on mobile devices. Compared with stochastic tilling, the proposed algorithm illustrates better visual effects in aperiodicity.