src/widgets/slider.cpp

   1 /*
   2  * This file is part of OpenTTD.
   3  * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
   4  * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
   5  * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
   6  */
   7
   8 /** @file slider.cpp Implementation of the horizontal slider widget. */
   9
  10 #include "../stdafx.h"
  11 #include "../palette_func.h"
  12 #include "../window_gui.h"
  13 #include "../window_func.h"
  14 #include "../strings_func.h"
  15 #include "../zoom_func.h"
  16 #include "slider_func.h"
  17
  18 #include "../safeguards.h"
  19
  20 static const int SLIDER_WIDTH = 3;
  21
  22 /**
  23  * Draw a slider widget with knob at given value
  24  * @param r Rectangle to draw the widget in
  25  * @param min_value Minimum value of slider
  26  * @param max_value Maximum value of slider
  27  * @param value Value to put the slider at
  28  * @param labels List of positions and labels to draw along the slider.
  29  */
  30 void DrawSliderWidget(Rect r, int min_value, int max_value, int value, const std::map<int, StringID> &labels)
  31 {
  32         /* Allow space for labels. We assume they are in the small font. */
  33         if (!labels.empty()) r.bottom -= GetCharacterHeight(FS_SMALL) + WidgetDimensions::scaled.hsep_normal;
  34
  35         max_value -= min_value;
  36
  37         /* Draw a wedge indicating low to high value. */
  38         const int ha = (r.bottom - r.top) / 5;
  39         const int sw = ScaleGUITrad(SLIDER_WIDTH);
  40         const int t = WidgetDimensions::scaled.bevel.top; /* Thickness of lines */
  41         int wx1 = r.left  + sw / 2;
  42         int wx2 = r.right - sw / 2;
  43         if (_current_text_dir == TD_RTL) std::swap(wx1, wx2);
  44         const uint shadow = _colour_gradient[COLOUR_GREY][3];
  45         const uint fill = _colour_gradient[COLOUR_GREY][6];
  46         const uint light = _colour_gradient[COLOUR_GREY][7];
  47         const std::vector<Point> wedge{ Point{wx1, r.bottom - ha}, Point{wx2, r.top + ha}, Point{wx2, r.bottom - ha} };
  48         GfxFillPolygon(wedge, fill);
  49         GfxDrawLine(wedge[0].x, wedge[0].y, wedge[2].x, wedge[2].y, light, t);
  50         GfxDrawLine(wedge[1].x, wedge[1].y, wedge[2].x, wedge[2].y, _current_text_dir == TD_RTL ? shadow : light, t);
  51         GfxDrawLine(wedge[0].x, wedge[0].y, wedge[1].x, wedge[1].y, shadow, t);
  52
  53         int x;
  54         for (auto label : labels) {
  55                 x = label.first - min_value;
  56                 if (_current_text_dir == TD_RTL) x = max_value - x;
  57                 x = r.left + (x * (r.right - r.left - sw) / max_value) + sw / 2;
  58                 GfxDrawLine(x, r.bottom - ha + 1, x, r.bottom + (label.second == STR_NULL ? 0 : WidgetDimensions::scaled.hsep_normal), shadow, t);
  59                 if (label.second != STR_NULL) {
  60                         Dimension d = GetStringBoundingBox(label.second, FS_SMALL);
  61                         x = Clamp(x - d.width / 2, r.left, r.right - d.width);
  62                         DrawString(x, x + d.width, r.bottom + 1 + WidgetDimensions::scaled.hsep_normal, label.second, TC_BLACK, SA_CENTER, false, FS_SMALL);
  63                 }
  64         }
  65
  66         /* Draw a slider handle indicating current value. */
  67         value -= min_value;
  68         if (_current_text_dir == TD_RTL) value = max_value - value;
  69         x = r.left + (value * (r.right - r.left - sw) / max_value);
  70         DrawFrameRect(x, r.top, x + sw, r.bottom, COLOUR_GREY, FR_NONE);
  71 }
  72
  73 /**
  74  * Handle click on a slider widget to change the value
  75  * @param r      Rectangle of the widget
  76  * @param pt     Clicked point
  77  * @param value[in,out] Value to modify
  78  * @return       True if the value setting was modified
  79  */
  80 bool ClickSliderWidget(Rect r, Point pt, int min_value, int max_value, int &value)
  81 {
  82         max_value -= min_value;
  83
  84         const int sw = ScaleGUITrad(SLIDER_WIDTH);
  85         int new_value = Clamp((pt.x - r.left - sw / 2) * max_value / (r.right - r.left - sw), 0, max_value);
  86         if (_current_text_dir == TD_RTL) new_value = max_value - new_value;
  87         new_value += min_value;
  88
  89         if (new_value != value) {
  90                 value = new_value;
  91                 return true;
  92         }
  93
  94         return false;
  95 }