Method and device for drawing molecular formula annotation on electronic map

Abstract

The invention provides a method and a device for drawing a molecular formula annotation on an electronic map. The method comprises the following steps that: obtaining a position coordinate which needsto draw the annotation on the electronic map, and converting the position coordinate into a pixel coordinate (x,y); independently taking two attribute field values of which the annotations need to bedisplayed as the numerator and the denominator of the molecular formula, measuring the length of the numerator character and the denominator character in the molecular formula, and converting into ascreen pixel distance; measuring the height of the denominator character in the molecular formula, and converting into a screen pixel distance; calculating the length of a fraction line; calculating the drawing positions of the numerator character, the fraction line and the denominator character; and drawing the numerator, the denominator and the fraction line to the corresponding positions of theelectronic map to form an integral molecular formula annotation. By use of the method, two attribute field values can be displayed through one modular formula annotation so as to be more visually andattractively displayed, annotation display is clear, and a drawing method is integrally simple and is unlikely to make mistakes.

Description

technical field

[0001] The invention relates to the field of electronic map display, in particular to a method and device for drawing molecular formula notes on an electronic map. Background technique

[0002] Electronic map annotation is one of the map languages, which is directly related to the aesthetics and practicality of the map. Therefore, annotation is an important content in the production of electronic maps. However, the existing electronic map annotation generally only displays one key field value. For annotations that need to display two attribute field values, the bracket mode or the two-line mode is generally used, which is not intuitive and beautiful for users. Contents of the invention

[0003] The purpose of the present invention is to provide a method and device for drawing molecular formula annotations on an electronic map, aiming to solve the problem that the existing annotations using bracket mode or two-line mode to display two attribute field values...

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