diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/graph_gui.cpp | 37 |
1 files changed, 21 insertions, 16 deletions
diff --git a/src/graph_gui.cpp b/src/graph_gui.cpp index f01f2b2f5..3fb750aad 100644 --- a/src/graph_gui.cpp +++ b/src/graph_gui.cpp @@ -69,8 +69,6 @@ static void DrawGraph(const GraphDrawer *gw) int right; int64 highest_value; int adj_height; - uint64 y_scaling; - int64 value; uint sel; /* the colors and cost array of GraphDrawer must accomodate @@ -121,7 +119,11 @@ static void DrawGraph(const GraphDrawer *gw) assert(gw->num_on_x_axis > 0); assert(gw->num_dataset > 0); - highest_value = 0; + /* Start of with a value of twice the height of the graph in pixels. It's a + * 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; /* bit selection for the showing of various players, base max element * on to-be shown player-information. This way the graph can scale */ @@ -142,19 +144,19 @@ static void DrawGraph(const GraphDrawer *gw) sel >>= 1; } - /* setup scaling */ - y_scaling = INVALID_VALUE; - value = adj_height * 2; - - if (highest_value > value) { - highest_value = ALIGN(highest_value, 8); - y_scaling = (((uint64) (value>>1) << 32) / highest_value); - value = highest_value; - } + /* 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); /* draw text strings on the y axis */ - int64 y_label = value; - if (gw->include_neg) y_label /= 2; + 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 (gw->include_neg) y_label_separation *= 2; + x = gw->left + GRAPH_X_POSITION_BEGINNING + 1; y = gw->top - 3; @@ -162,7 +164,8 @@ static void DrawGraph(const GraphDrawer *gw) SetDParam(0, gw->format_str_y_axis); SetDParam64(1, y_label); DrawStringRightAligned(x, y, STR_0170, GRAPH_AXIS_LABEL_COLOUR); - y_label -= (value / (GRAPH_NUM_LINES_Y - 1)); + + y_label -= y_label_separation; y += (gw->height / (GRAPH_NUM_LINES_Y - 1)); } @@ -215,7 +218,9 @@ static void DrawGraph(const GraphDrawer *gw) int64 datapoint = gw->cost[i][j]; if (datapoint != INVALID_VALUE) { - y = adj_height - BIGMULSS64(datapoint, y_scaling >> 1, 31) + gw->top; + /* 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; GfxFillRect(x-1, y-1, x+1, y+1, color); if (old_x != INVALID_VALUE) |