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POHow to determine Scale of Line Graph based on Pixels/Height?
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copied!<p>I have a problem due to my terrible math abilities, that I cannot figure out how to scale a graph based on the maximum and minimum values so that the whole graph will fit onto the graph-area (400x420) without parts of it being off the screen (based on a given equation by user).</p> <p>Let's say I have this code, and it automatically draws squares and then the line graph based on these values. What is the formula (what do I multiply) to scale it so that it fits into the small graphing area?</p> <pre><code>vector<int> m_x; vector<int> m_y; // gets automatically filled by user equation or values int HeightInPixels = 420;// Graphing area size!! int WidthInPixels = 400; int best_max_y = GetMaxOfVector(m_y); int best_min_y = GetMinOfVector(m_y); m_row = 0; m_col = 0; y_magnitude = (HeightInPixels/(best_max_y+best_min_y)); // probably won't work x_magnitude = (WidthInPixels/(int)m_x.size()); m_col = m_row = best_max_y; // number of vertical/horizontal lines to draw ////x_magnitude = (WidthInPixels/(int)m_x.size())/2; Doesn't work well ////y_magnitude = (HeightInPixels/(int)m_y.size())/2; Doesn't work well ready = true; // we have values, graph it Invalidate(); // uses WM_PAINT //////////////////////////////////////////// /// Construction of Graph layout on WM_PAINT, before painting line graph /////////////////////////////////////////// CPen pSilver(PS_SOLID, 1, RGB(150, 150, 150) ); // silver CPen pDarkSilver(PS_SOLID, 2, RGB(120, 120, 120) ); // dark silver dc.SelectObject( pSilver ); // silver color CPoint pt( 620, 620 ); // origin int left_side = 310; int top_side = 30; int bottom_side = 450; int right_side = 710; // create a rectangle border dc.Rectangle(left_side,top_side,right_side,bottom_side); int origin = 310; int xshift = 30; int yshift = 30; // draw scaled rows and columns for(int r = 1; r <= colrow; r++){ // draw rows pt.x = left_side; pt.y = (ymagnitude)*r+top_side; dc.MoveTo( pt ); pt.x = right_side; dc.LineTo( pt ); for(int c = 1; c <= colrow; c++){ pt.x = left_side+c*(magnitude); pt.y = top_side; dc.MoveTo(pt); pt.y = bottom_side; dc.LineTo(pt); } // draw columns } // grab the center of the graph on x and y dimension int top_center = ((right_side-left_side)/2)+left_side; int bottom_center = ((bottom_side-top_side)/2)+top_side; </code></pre>

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