diff options
| -rw-r--r-- | src/graph_gui.cpp | 118 |
1 files changed, 78 insertions, 40 deletions
diff --git a/src/graph_gui.cpp b/src/graph_gui.cpp index de1479461..cee6dee45 100644 --- a/src/graph_gui.cpp +++ b/src/graph_gui.cpp @@ -23,6 +23,7 @@ #include "gfx_func.h" #include "sortlist_type.h" #include "core/geometry_func.hpp" +#include <math.h> #include "table/strings.h" #include "table/sprites.h" @@ -154,6 +155,12 @@ static void ShowGraphLegend() AllocateWindowDescFront<GraphLegendWindow>(&_graph_legend_desc, 0); } +/** Contains the interval of a graph's data. */ +struct ValuesInterval { + OverflowSafeInt64 highest; ///< Highest value of this interval. Must be zero or greater. + OverflowSafeInt64 lowest; ///< Lowest value of this interval. Must be zero or less. +}; + /******************/ /* BASE OF GRAPHS */ /*****************/ @@ -200,13 +207,15 @@ protected: OverflowSafeInt64 cost[GRAPH_MAX_DATASETS][GRAPH_NUM_MONTHS]; ///< Stored costs for the last #GRAPH_NUM_MONTHS months /** - * Get the highest value of the graph's data. Excluded data is ignored to allow showing smaller values in + * Get the interval that contains the graph's data. Excluded data is ignored to show smaller values in * better detail when disabling higher ones. - * @return Highest value of the graph (ignoring disabled data). + * @return Highest and lowest values of the graph (ignoring disabled data). */ - int64 GetHighestValue() const + ValuesInterval GetValuesInterval() const { - OverflowSafeInt64 highest_value = 0; + ValuesInterval current_interval; + current_interval.highest = INT64_MIN; + current_interval.lowest = INT64_MAX; for (int i = 0; i < this->num_dataset; i++) { if (HasBit(this->excluded_data, i)) continue; @@ -214,35 +223,70 @@ protected: OverflowSafeInt64 datapoint = this->cost[i][j]; if (datapoint != INVALID_DATAPOINT) { - /* For now, if the graph has negative values the scaling is - * symmetrical about the x axis, so take the absolute value - * of each data point. */ - highest_value = max(highest_value, abs(datapoint)); + current_interval.highest = max(current_interval.highest, datapoint); + current_interval.lowest = min(current_interval.lowest, datapoint); } } } - /* Prevent showing the highest value too close to the graph upper limit. */ - highest_value = (11 * highest_value) / 10; - /* Avoid using zero as the highest value. */ - if (highest_value == 0) highest_value = GRAPH_NUM_LINES_Y - 1; - /* Round up highest_value so that it will divide cleanly into the number of - * axis labels used. */ - int round_val = highest_value % (GRAPH_NUM_LINES_Y - 1); - if (round_val != 0) highest_value += (GRAPH_NUM_LINES_Y - 1 - round_val); + /* Prevent showing values too close to the graph limits. */ + current_interval.highest = (11 * current_interval.highest) / 10; + current_interval.lowest = (11 * current_interval.lowest) / 10; + + /* Always include zero in the shown range. */ + OverflowSafeInt64 abs_lower = (current_interval.lowest > 0) ? (OverflowSafeInt64)0 : abs(current_interval.lowest); + OverflowSafeInt64 abs_higher = (current_interval.highest < 0) ? (OverflowSafeInt64)0 : current_interval.highest; + + int num_pos_grids; + int grid_size; + const int num_grids = GRAPH_NUM_LINES_Y - 1; + + if (abs_lower == 0) { + if (abs_higher == 0) { + /* If both values are zero, show an empty graph. */ + num_pos_grids = num_grids / 2; + grid_size = 1; + } else { + /* The positive part of the graph can use all grids. */ + num_pos_grids = num_grids; + grid_size = ceil((float)abs_higher / num_grids); + } + + } else { + if (abs_higher == 0) { + /* The negative part of the graph can use all grids. */ + num_pos_grids = 0; + grid_size = ceil((float)abs_lower / num_grids); + } else { + /* Get the smallest grid size required and the number of grids for each part of the graph. */ + int min_pos_grids = 1; + int min_grid_size = INT_MAX; + for (num_pos_grids = 1; num_pos_grids <= num_grids - 1; num_pos_grids++) { + /* Size required for each part of the graph given this number of grids. */ + int pos_grid_size = ceil((float)abs_higher / num_pos_grids); + int neg_grid_size = ceil((float)abs_lower / (num_grids - num_pos_grids)); + grid_size = max(pos_grid_size, neg_grid_size); + if (grid_size < min_grid_size) { + min_pos_grids = num_pos_grids; + min_grid_size = grid_size; + } + } + grid_size = min_grid_size; + num_pos_grids = min_pos_grids; + } + } - return highest_value; + current_interval.highest = num_pos_grids * grid_size; + current_interval.lowest = -(num_grids - num_pos_grids) * grid_size; + return current_interval; } - uint GetYLabelWidth(int64 highest_value) const + /** Get width for Y labels */ + uint GetYLabelWidth(ValuesInterval current_interval) const { /* draw text strings on the y axis */ - int64 y_label = highest_value; - int64 y_label_separation = highest_value / (GRAPH_NUM_LINES_Y - 1); - - /* If there are negative values, the graph goes from highest_value to - * -highest_value, not highest_value to 0. */ - if (this->has_negative_values) y_label_separation *= 2; + int64 y_label = current_interval.highest; + int64 y_label_separation = (current_interval.highest - current_interval.lowest) / (GRAPH_NUM_LINES_Y - 1); uint max_width = 0; @@ -264,9 +308,9 @@ protected: */ void DrawGraph(Rect r) const { - uint x, y; ///< Reused whenever x and y coordinates are needed. - OverflowSafeInt64 highest_value; ///< Highest value to be drawn. - int x_axis_offset; ///< Distance from the top of the graph to the x axis. + uint x, y; ///< Reused whenever x and y coordinates are needed. + ValuesInterval interval; ///< Interval that contains all of the graph data. + int x_axis_offset; ///< Distance from the top of the graph to the x axis. /* the colours and cost array of GraphDrawer must accomodate * both values for cargo and companies. So if any are higher, quit */ @@ -282,10 +326,9 @@ protected: r.left += 9; r.right -= 5; - highest_value = GetHighestValue(); + interval = GetValuesInterval(); - /* Get width for Y labels */ - int label_width = GetYLabelWidth(highest_value); + int label_width = GetYLabelWidth(interval); r.left += label_width; @@ -297,9 +340,9 @@ protected: r.right = r.left + x_sep * this->num_vert_lines; r.bottom = r.top + y_sep * (GRAPH_NUM_LINES_Y - 1); + OverflowSafeInt64 interval_size = interval.highest + abs(interval.lowest); /* Where to draw the X axis */ - x_axis_offset = r.bottom - r.top; - if (this->has_negative_values) x_axis_offset /= 2; + x_axis_offset = (r.bottom - r.top) * interval.highest / interval_size; /* Draw the vertical grid lines. */ @@ -335,12 +378,8 @@ protected: assert(this->num_dataset > 0); /* draw text strings on the y axis */ - int64 y_label = highest_value; - int64 y_label_separation = highest_value / (GRAPH_NUM_LINES_Y - 1); - - /* If there are negative values, the graph goes from highest_value to - * -highest_value, not highest_value to 0. */ - if (this->has_negative_values) y_label_separation *= 2; + int64 y_label = interval.highest; + int64 y_label_separation = abs(interval.highest - interval.lowest) / (GRAPH_NUM_LINES_Y - 1); y = r.top - GetCharacterHeight(FS_SMALL) / 2; @@ -421,8 +460,7 @@ protected: } else { datapoint >>= reduce_range; } - - y = r.top + x_axis_offset - (x_axis_offset * datapoint) / (highest_value >> reduce_range); + y = r.top + x_axis_offset - ((r.bottom - r.top) * datapoint) / (interval_size >> reduce_range); /* Draw the point. */ GfxFillRect(x - 1, y - 1, x + 1, y + 1, colour); |