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-rw-r--r--src/graph_gui.cpp59
1 files changed, 30 insertions, 29 deletions
diff --git a/src/graph_gui.cpp b/src/graph_gui.cpp
index 7c2dbc99b..7427e7088 100644
--- a/src/graph_gui.cpp
+++ b/src/graph_gui.cpp
@@ -46,7 +46,7 @@ typedef struct GraphDrawer {
uint excluded_data; // bitmask of the datasets that shouldn't be displayed.
byte num_dataset;
byte num_on_x_axis;
- bool include_neg;
+ bool has_negative_values;
byte num_vert_lines;
/* The starting month and year that values are plotted against. If month is
@@ -59,8 +59,8 @@ typedef struct GraphDrawer {
uint16 x_values_start;
uint16 x_values_increment;
- int left, top;
- uint height;
+ int left, top; // Where to start drawing the graph, in pixels.
+ uint height; // The height of the graph in pixels.
StringID format_str_y_axis;
byte colors[GRAPH_MAX_DATASETS];
int64 cost[GRAPH_MAX_DATASETS][24]; // last 2 years
@@ -68,23 +68,22 @@ typedef struct GraphDrawer {
static void DrawGraph(const GraphDrawer *gw)
{
- uint x, y; // Reused whenever x and y coordinates are needed.
- int right;
- int64 highest_value;
- int adj_height;
+ uint x, y; // Reused whenever x and y coordinates are needed.
+ int64 highest_value; // Highest value to be drawn.
+ int x_axis_offset; // Distance from the top of the graph to the x axis.
/* the colors and cost array of GraphDrawer must accomodate
* both values for cargo and players. So if any are higher, quit */
assert(GRAPH_MAX_DATASETS >= (int)NUM_CARGO && GRAPH_MAX_DATASETS >= (int)MAX_PLAYERS);
-
assert(gw->num_vert_lines > 0);
byte grid_colour = _colour_gradient[14][4];
- /* Position of the bottom of the graph. */
+ /* The coordinates of the opposite edges of the graph. */
int bottom = gw->top + gw->height - 1;
+ int right = gw->left + GRAPH_X_POSITION_BEGINNING + gw->num_vert_lines * GRAPH_X_POSITION_SEPARATION - 1;
- /* draw the vertical lines */
+ /* Draw the vertical grid lines. */
/* Don't draw the first line, as that's where the axis will be. */
x = gw->left + GRAPH_X_POSITION_BEGINNING + GRAPH_X_POSITION_SEPARATION;
@@ -94,27 +93,29 @@ static void DrawGraph(const GraphDrawer *gw)
x += GRAPH_X_POSITION_SEPARATION;
}
- /* draw the horizontal lines */
+ /* Draw the horizontal grid lines. */
x = gw->left + GRAPH_X_POSITION_BEGINNING;
y = gw->height + gw->top;
- right = gw->left + GRAPH_X_POSITION_BEGINNING + gw->num_vert_lines * GRAPH_X_POSITION_SEPARATION - 1;
for (int i = 0; i < GRAPH_NUM_LINES_Y; i++) {
GfxFillRect(x, y, right, y, grid_colour);
y -= (gw->height / (GRAPH_NUM_LINES_Y - 1));
}
- /* draw vertical edge line */
+ /* Draw the y axis. */
GfxFillRect(x, gw->top, x, bottom, GRAPH_AXIS_LINE_COLOUR);
- adj_height = gw->height;
- if (gw->include_neg) adj_height >>= 1;
+ /* Find the distance from the top of the graph to the x axis. */
+ x_axis_offset = gw->height;
+
+ /* The graph is currently symmetrical about the x axis. */
+ if (gw->has_negative_values) x_axis_offset /= 2;
- /* draw horiz edge line */
- y = adj_height + gw->top;
+ /* Draw the x axis. */
+ y = x_axis_offset + gw->top;
GfxFillRect(x, y, right, y, GRAPH_AXIS_LINE_COLOUR);
- /* find the max element */
+ /* Find the largest value that will be drawn. */
if (gw->num_on_x_axis == 0)
return;
@@ -125,7 +126,7 @@ static void DrawGraph(const GraphDrawer *gw)
* bit arbitrary, but it makes the cargo payment graph look a little nicer,
* and prevents division by zero when calculating where the datapoint
* should be drawn. */
- highest_value = adj_height * 2;
+ highest_value = x_axis_offset * 2;
for (int i = 0; i < gw->num_dataset; i++) {
if (!HASBIT(gw->excluded_data, i)) {
@@ -153,7 +154,7 @@ static void DrawGraph(const GraphDrawer *gw)
/* If there are negative values, the graph goes from highest_value to
* -highest_value, not highest_value to 0. */
- if (gw->include_neg) y_label_separation *= 2;
+ if (gw->has_negative_values) y_label_separation *= 2;
x = gw->left + GRAPH_X_POSITION_BEGINNING + 1;
y = gw->top - 3;
@@ -215,9 +216,9 @@ static void DrawGraph(const GraphDrawer *gw)
int64 datapoint = gw->cost[i][j];
if (datapoint != INVALID_DATAPOINT) {
- /* XXX: This can overflow if adj_height * datapoint is too
- * big to fit in an int64. */
- y = gw->top + adj_height - (adj_height * datapoint) / highest_value;
+ /* XXX: This can overflow if x_axis_offset * datapoint is
+ * too big to fit in an int64. */
+ y = gw->top + x_axis_offset - (x_axis_offset * datapoint) / highest_value;
/* Draw the point. */
GfxFillRect(x-1, y-1, x+1, y+1, color);
@@ -368,7 +369,7 @@ static void OperatingProfitWndProc(Window *w, WindowEvent *e)
gd.left = 2;
gd.top = 18;
gd.height = 136;
- gd.include_neg = true;
+ gd.has_negative_values = true;
gd.format_str_y_axis = STR_CURRCOMPACT;
SetupGraphDrawerForPlayers(&gd);
@@ -439,7 +440,7 @@ static void IncomeGraphWndProc(Window *w, WindowEvent *e)
gd.left = 2;
gd.top = 18;
gd.height = 104;
- gd.include_neg = false;
+ gd.has_negative_values = false;
gd.format_str_y_axis = STR_CURRCOMPACT;
SetupGraphDrawerForPlayers(&gd);
@@ -509,7 +510,7 @@ static void DeliveredCargoGraphWndProc(Window *w, WindowEvent *e)
gd.left = 2;
gd.top = 18;
gd.height = 104;
- gd.include_neg = false;
+ gd.has_negative_values = false;
gd.format_str_y_axis = STR_7024;
SetupGraphDrawerForPlayers(&gd);
@@ -579,7 +580,7 @@ static void PerformanceHistoryWndProc(Window *w, WindowEvent *e)
gd.left = 2;
gd.top = 18;
gd.height = 200;
- gd.include_neg = false;
+ gd.has_negative_values = false;
gd.format_str_y_axis = STR_7024;
SetupGraphDrawerForPlayers(&gd);
@@ -652,7 +653,7 @@ static void CompanyValueGraphWndProc(Window *w, WindowEvent *e)
gd.left = 2;
gd.top = 18;
gd.height = 200;
- gd.include_neg = false;
+ gd.has_negative_values = false;
gd.format_str_y_axis = STR_CURRCOMPACT;
SetupGraphDrawerForPlayers(&gd);
@@ -733,7 +734,7 @@ static void CargoPaymentRatesWndProc(Window *w, WindowEvent *e)
gd.left = 2;
gd.top = 24;
gd.height = 104;
- gd.include_neg = false;
+ gd.has_negative_values = false;
gd.format_str_y_axis = STR_CURRCOMPACT;
gd.num_dataset = NUM_CARGO;
gd.num_on_x_axis = 20;