Using Different DC Draws up the Graph
Meng Xiang-zeng · Computer Knowledge and Technology · 2006
Drawing a line in the procedure is different with drawing a line on the paper which needs to determine two spots,and the Windows procedure is based on the news programming, therefore drawing a line needs to catch two news:mouse left key pressing down (WMLButtonDown) and mouse left key shoots (WMLButtonUp).Through responsing to two news gains two spots,two determines one straight line. Because DC is different as well as the structure object is different causes the line which draws to be also different.Proposed the mapping scope key was which window is dc related with.To used the straight line which the different Class drew carries on the comparison.