Method for realizing scaling of electronic map drawn by GDI (graphic device interface)+

Abstract

The invention discloses a method for realizing scaling of an electronic map drawn by GDI (graphic device interface)+. The method includes that a proportion relationship between drawing surface, namely display surface and canvas size for graphic drawing in GDI+ is utilized to realize scaling of the electronic map; size of the drawing surface in the GDI+ is known, using the GDI+ for graphic drawing can be taken as drawing on the canvas, size of the canvas can be changed by changing acquired width and height of the drawing surface, and the size of the canvas can be recorded while operations like translation and scaling rotation can be performed on the canvas in the GDI+, and the drawing surface can display the whole canvas or a certain part of the canvas. By the method, scaling and optimizing of display effect after scaling can be effectively realized, and scaling and displaying after scaling of a selected area are simplified. In addition, the method is suitable for interactive operation of the electronic map and other graphs.

Description

technical field [0001] The invention discloses a method for realizing GDI+ drawing electronic map scaling, which relates to the field of image processing. Background technique [0002] Using GDI+ (Graphics Device Interface, graphics device interface), the main task of GDI+ is to be responsible for the information exchange between the system and the drawing program, and to handle the graphics output of all Windows programs. When the drawn electronic map realizes the interactive operation, the translation and rotation can be realized directly and relatively perfectly by using the methods in the Graphics class in GDI+. However, after using the method of the Graphics class during zooming, the displayed dot symbols become larger and the line symbols become thicker, etc. These changes will cause abnormal display of the electronic map. The general method used to solve the above problems is to use computer graphics zoom matrix to recalculate the coordinates of the displayed electro...

AI Technical Summary

Problems solved by technology

The general method used to solve the above problems is to use the computer graphics zoom matrix to recalculate the coordinates of the displayed electronic map. Although this method can achieve the zoom effect, it involves zooming the selected area after zooming. Displaying on the original display surface also needs to recalculate each drawing point, which is inconvenient to use and requires a large amount of calculation

In the prior art, there is a lack of a convenient method that can realize the zooming and zooming of the electronic map and optimize the display results according to the size change of the drawing canvas and the simple recalculation of the coordinates

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