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-rw-r--r--src/graph_gui.cpp118
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);