CN105046652A - Coulomb force model-based graphic node occlusion elimination method - Google Patents

Abstract

The invention belongs to the technical field of graph layout in graphics and especially relates to a Coulomb force model-based graphic node occlusion elimination method. The method comprises the steps of moving an occlusion node and eliminating the occlusion node. According to the technical scheme of the method, the movement distances of nodes in both the horizontal direction and the vertical direction, the overall area value of a graph and the running time are enabled to be relatively small based on the above node movement strategy. Meanwhile, a Coulomb force model is applied to the node occlusion elimination method, so that the purposes of eliminating the occlusion and keeping the nodes in an initial sequence are realized at the same time. During the Coulomb force model-based occlusion elimination process, the original separation distance between two nodes is added with a constant, so that the two nodes are ensured to be completely separated from each other. Therefore, the graph layout is ensured to be reasonable.

Description

A kind of graphical nodes based on Coulomb force model blocks removing method

Technical field

The invention belongs to pattern layout's technical field in graphics, particularly a kind of graphical nodes based on Coulomb force model blocks removing method.

Background technology

Along with the fast development of graphics, the placement algorithm in figure is made also to become a study hotspot gradually.To in pattern layout's technique study, node on behalf has entity or the object of label, but a lot of algorithm is used as a point in layout, have ignored their size.Therefore, when using traditional algorithm to place these nodes, by the problem that generation node blocks.This problem conceals the information relationship between figure interior joint, makes user cannot observe useful information from the figure blocked.In order to overcome the above problems, Many researchers is studied it, and then proposes corresponding node and block elimination algorithm and adjust initial pattern layout, solves the problem causing owing to blocking and cannot study figure interior joint.But, these algorithms have following deficiency: in the horizontal direction or in vertical direction after comparatively large, the distributing adjustment of the distance of node motion the expanding value time complexity that is comparatively large, algorithm of area higher, cannot keep and the similarity etc. of initialization layout, therefore, finding an efficient algorithm to solve the problems referred to above, is a problem urgently to be resolved hurrily in pattern layout's algorithm field.

The problem that the people such as DwyerT are blocked for pattern layout's interior joint, propose the algorithm that the elimination figure interior joint based on VPSC (VariablePlacementWithSeparationConstraints) blocks, this algorithm comprises two parts: the generation of unshielding joint constraint condition and eliminate the scheme that these block node.Part I uses scan-line algorithm and node occlusion detection method to generate the constraint condition eliminated node and block, Part II is the constraint condition according to blocking node, calculate the expectation weighted value of each node to reach the object of knot modification position, thus eliminate the problem of blocking in figure.But this algorithm and start node to choose order relevant, and be scan on a fixing direction, finally make node figure after the adjustment stretch in one direction comparatively large, the displacement of whole figure and area expansion all can be larger.

The people such as HuangX propose power conversion FT (Force-Transfer) algorithm, and the method has calculated a dummy node according to the node coordinate value in figure, with this dummy node for starting point, and the node in scanning patter.Scanning strategy is divided into: upwards scan, scan downwards, scan left and scan this four order to the right, after obtaining blocking node, obtaining the neighbor node that it blocks node according to scanning sequency.Then, select the less value of the amount of blocking block with the two nodes eliminations that make provided and reach the constant m of released state, utilize power model to be separated by the node blocked, and upgrade its neighbor node.After four scanning all terminates, the target eliminated and block node in figure can be reached.But, utilize the node after the adjustment of this algorithm can not keep the similarity with initial layout, and its efficiency is relevant with the selection strategy of dummy node.

Summary of the invention

A kind of graphical nodes based on Coulomb force model is the object of the present invention is to provide to block removing method.

The object of the present invention is achieved like this:

Graphical nodes based on Coulomb force model blocks removing method, comprising:

(1) node is blocked in movement:

1.1) according to from lower left top-right order, node is scanned in the graphic, if the horizontal coordinate value of two nodes is identical, then the node priority scan that vertical coordinate value is less; If two node vertical coordinate values are identical, then the node priority scan that the value of horizontal coordinate is less;

1.2) node that in the process of blocking, stationary coordinate are less is being eliminated, the node that moving coordinate is larger;

(2) node is blocked in elimination:

2.1) nodes all in figure is scanned, the node mutually blocked finding limit to be connected, and these nodes are stored;

2.2) for the node mutually blocked, calculate and block nodal distance L when two nodes have just reached released state, and locate the point charge of the appropriate equivalent of the same race of each placement one at the center point;

2.3) on the basis of blocking nodal distance L, turn increase a constant n (n>0), the distance making to eliminate after blocking between two nodes reaches L+n;

2.4) node blocked is moved, thus the node blocked is separated.

The invention has the beneficial effects as follows:

The node motion strategy provided in method, make the total area value of the displacement of node in horizontal and vertical direction, figure and working time all smaller; Coulomb force models applying is blocked in the method for elimination at node, reaches the initialization order also maintaining node while elimination is blocked; Utilizing Coulomb force model to eliminate in the process of blocking, when two nodes reach separation distance basis on add a constant, ensure that two nodes reach the state be separated completely, thus draw a rational layout graph.

Accompanying drawing explanation

Fig. 1 is the schematic diagram blocking node;

Fig. 2 makes to block schematic diagram when node reaches firm released state;

Fig. 3 is the schematic diagram of repulsion in the model of Coulomb force;

Fig. 4 is the initialize graphic containing blocking node;

Fig. 5 uses the method in the present invention to eliminate the figure after blocking node;

Fig. 6 is the process flow diagram that node blocks removing method.

Embodiment

Below in conjunction with accompanying drawing, the present invention is described further.

The present invention is directed in VPSC algorithm and only scan in one direction, make the problem that node motion Distance geometry area expanding value is larger; The problem with initial layout's similarity can not be kept in FT algorithm, propose a kind of node based on Coulomb force model and block removing method.

This method comprises the content of two aspects: block node motion method and block node and eliminate.

(1) method of blocking node motion comprises following content:

1) for figure interior joint occlusion issue, the method that it is scanned is given: namely according to from lower left top-right order, node is scanned in the graphic in method, if the horizontal coordinate value of two nodes is identical, then the node priority scan that vertical coordinate value is less; If two node vertical coordinate values are identical, then the node priority scan that the value of horizontal coordinate is less;

2) blocking the efficiency of method in elimination process in order to improve node, The present invention gives the moving method blocking node: according to scan method in this paper, eliminating the node that in the process of blocking, stationary coordinate are less, the node that moving coordinate is larger.Thus reduce the number of times of its circulation.

(2) block node elimination to comprise the following steps:

1) according to the scan method in literary composition, nodes all in figure is scanned, the node mutually blocked finding limit to be connected, and these nodes are stored;

2) for the node mutually blocked, calculate and block nodal distance L when two nodes have just reached released state, and locate the point charge of the appropriate equivalent of the same race of each placement one at the center point;

3) in order to eliminate the eclipse phenomena of node completely, the basis of blocking nodal distance L turn increases a constant n (n>0), the distance making to eliminate after blocking between two nodes reaches L+n;

4) character utilizing Coulomb force model and the moving method blocking node move the node blocked, thus are separated by the node blocked.

Process flow diagram below with reference to the accompanying drawings in 6 illustrates the process of this method:

Scan all nodes in figure according to proposed scan method, the node mutually blocked according to following formula is to set V={ (N _i, N _j) | N _i∈ Ν, N _j∈ Ν, i, j=1,2,3 ..., | N|}, wherein, N is the set of the figure interior joint of scanning, N _iand N _jrepresentation node i and j respectively.If V is empty, then now unscreened node in figure is described, method performs end.

|x _i-x _j|＜(w _i+w _j)/2+d

or|y _i-y _j|＜(h _i+h _j)/2+d

Wherein, (x _i, y _i) represent the center point coordinate of node i, w _iand h _irepresent width and the height of node i respectively, d is the minimum constant that node i and j keep not blocking.

Below the step of blocking node elimination:

1) obtain gathering the node pair mutually blocked arbitrarily in V, calculate the distance L that it blocks node.What be connected for there being limit in Fig. 1 blocks node, can draw block nodal distance L when to reach firm released state between two node i and j according to following steps _{(i, j)};

Step one: for the node blocked, as shown in Figure 1, can according to block node dimension information, obtain its occlusion coefficient.

$O_{E(i,j)}=\max (\min (\frac{w_i+w_j}{2*|x_i-x_j|},\frac{h_i+h_j}{2*|y_i-y_j|}),1)$

Step 2: calculate the formula of distance, the node obtained when two nodes reach released state blocks distance L _{(i, j)}, that is to say the length of two central point connecting lines as shown in Figure 2.

$L_{(i,j)}=O_{E(i,j)}*\sqrt{{(x_i-x_j)}^2+{(y_i-y_j)}^2}$

Wherein, O _{e (i, j)}represent that two block internodal occlusion coefficient, L _{(i, j)}represent and block distance between node i and node j.

2) arrange a constant n (n>0), make to eliminate completely the distance of 2 node center points after blocking and reach L+n, now two nodes can reach a state be separated;

3) compare the center point coordinate of the node that two block mutually, obtain the node that coordinate is less;

4) for the node mutually blocked, the point charge of appropriate equivalent of the same race is placed at place at the center point, makes it produce an enough large repulsive force, as shown in Figure 3;

5) in the process of node motion, the node motion method according to the present invention provides: in the node blocked, the node that stationary coordinate are less, the node that moving coordinate is larger simultaneously.Utilize the character of Coulomb force model and node motion method to move blocking node, thus eliminate the node blocked;

6) when the distance of two nodes reaches L+n, cancel the point charge of its central spot, two nodes now can be separated completely, as shown in Figure 4;

7) if traveled through V interior joint pair, then the node that blocks obtained in this time scanning is eliminated completely; Otherwise turn back to step 1) continue to perform;

8) node in figure is rescaned according to above-mentioned process.

Composition graphs 4 of the present invention and Fig. 5, citing provides the step eliminating node occlusion issue:

Step one: as shown in Figure 4, according to blocking node determination methods in the present invention, can draw: node 1 and node 2, node 2 and node 3 block.Place isocenter electric charge of the same race in the central spot of node 1 and node 2, make it produce an enough large Coulomb force, then according to node motion method and Coulomb force, the node 1 and 2 blocked is separated.

Step 2: for the node 2 and 3 mutually blocked, isocenter electric charge of the same race is placed at place at the center point, produces enough large Coulomb force, moves, solve the occlusion issue of node 2 and node 3 according to Coulomb force and node motion method to node 2 and node 3.

Step 3: rescan the node in figure, if without the node finding to block, then illustrate unscreened node in figure; The node blocked if find, then utilize the method in step one to move the node blocked.

Can be reached the problem eliminated and block node in Fig. 4 by above three steps, be eliminate the figure after blocking node as shown in Figure 5.

Adopt method above not only can reduce the displacement of node and the area of graphic extension, and optimize the operational efficiency of method, improve the reliability of method.

Owing to employing Coulomb force model in the method, it can make the node mutually blocked move along the direction of its central point connecting line, and therefore, method of the present invention can also keep the similarity of node and initialization layout interior joint.

Claims (1)

1. the graphical nodes based on Coulomb force model blocks a removing method, it is characterized in that:

(1) node is blocked in movement:

1.1) according to from lower left top-right order, node is scanned in the graphic, if the horizontal coordinate value of two nodes is identical, then the node priority scan that vertical coordinate value is less; If two node vertical coordinate values are identical, then the node priority scan that the value of horizontal coordinate is less;

1.2) node that in the process of blocking, stationary coordinate are less is being eliminated, the node that moving coordinate is larger;

(2) node is blocked in elimination:

2.1) nodes all in figure is scanned, the node mutually blocked finding limit to be connected, and these nodes are stored;

2.2) for the node mutually blocked, calculate and block nodal distance L when two nodes have just reached released state, and locate the point charge of the appropriate equivalent of the same race of each placement one at the center point;

2.3) on the basis of blocking nodal distance L, turn increase a constant n (n>0), the distance making to eliminate after blocking between two nodes reaches L+n;

2.4) node blocked is moved, thus the node blocked is separated.