Implemented anti-aliasing for cPixmap::DrawSlope()

5 files changed, 104 insertions, 23 deletions

diff --git a/CONTRIBUTORS b/CONTRIBUTORS
index b9907e95..f3507096 100644
--- a/CONTRIBUTORS
+++ b/CONTRIBUTORS
@@ -2441,6 +2441,7 @@ Christoph Haubrich <christoph1.haubrich@arcor.de>
  for suggesting to add a confirmation before renaming a recording to its folder name
  for reporting a problem with data loss in case renaming a recording fails
  for adding support for HEVC-video and AC-4-audio
+ for implementing anti-aliasing for cPixmap::DrawSlope()
 
 Pekka Mauno <pekka.mauno@iki.fi>
  for fixing cSchedule::GetFollowingEvent() in case there is currently no present
diff --git a/HISTORY b/HISTORY
index b764a911..e7e780ed 100644
--- a/HISTORY
+++ b/HISTORY
@@ -9513,7 +9513,7 @@ Video Disk Recorder Revision History
   with the main menu open.
 - Official release.
 
-2020-09-16:
+2020-09-29: Version 2.4.5
 
 - Updated the Italian OSD texts (thanks to Diego Pierotto).
 - Fixed handling newline characters in ci.c's CopyString() (reported by Winfried Köhler).
@@ -9521,3 +9521,6 @@ Video Disk Recorder Revision History
   by Winfried Köhler).
 - Fixed a possible invalid lock sequence in cMenuTimers::OnOff().
 - Fixed several typos (reported by Jens Schleusener).
+- Implemented anti-aliasing for cPixmap::DrawSlope() (thanks to Christoph Haubrich).
+  The version numbers (both VDRVERSNUM and APIVERSNUM) have been bumped to 2.4.5 to
+  indicate this change.
diff --git a/config.h b/config.h
index c9f3d3b1..f57aea73 100644
--- a/config.h
+++ b/config.h
@@ -4,7 +4,7 @@
  * See the main source file 'vdr.c' for copyright information and
  * how to reach the author.
  *
- * $Id: config.h 4.19 2020/07/15 15:13:08 kls Exp $
+ * $Id: config.h 4.20 2020/09/29 14:09:26 kls Exp $
  */
 
 #ifndef __CONFIG_H
@@ -22,13 +22,13 @@
 
 // VDR's own version number:
 
-#define VDRVERSION  "2.4.4"
-#define VDRVERSNUM   20404  // Version * 10000 + Major * 100 + Minor
+#define VDRVERSION  "2.4.5"
+#define VDRVERSNUM   20405  // Version * 10000 + Major * 100 + Minor
 
 // The plugin API's version number:
 
-#define APIVERSION  "2.4.3"
-#define APIVERSNUM   20403  // Version * 10000 + Major * 100 + Minor
+#define APIVERSION  "2.4.5"
+#define APIVERSNUM   20405  // Version * 10000 + Major * 100 + Minor
 
 // When loading plugins, VDR searches them by their APIVERSION, which
 // may be smaller than VDRVERSION in case there have been no changes to
diff --git a/osd.c b/osd.c
index 8a3ce721..e8c7f857 100644
--- a/osd.c
+++ b/osd.c
@@ -4,7 +4,7 @@
  * See the main source file 'vdr.c' for copyright information and
  * how to reach the author.
  *
- * $Id: osd.c 4.6 2019/05/24 21:28:35 kls Exp $
+ * $Id: osd.c 4.7 2020/09/29 14:09:26 kls Exp $
  */
 
 #include "osd.h"
@@ -1273,6 +1273,20 @@ void cPixmapMemory::DrawPixel(const cPoint &Point, tColor Color)
   Unlock();
 }
 
+void cPixmapMemory::DrawBlendedPixel(const cPoint &Point, tColor Color, uint8_t Alpha)
+{
+  Lock();
+  if (DrawPort().Size().Contains(Point)) {
+     int p = Point.Y() * DrawPort().Width() + Point.X();
+     if (Alpha != ALPHA_OPAQUE)
+        data[p] = AlphaBlend(Color, data[p], Alpha);
+     else
+        data[p] = Color;
+     MarkDrawPortDirty(Point);
+     }
+  Unlock();
+}
+
 void cPixmapMemory::DrawBitmap(const cPoint &Point, const cBitmap &Bitmap, tColor ColorFg, tColor ColorBg, bool Overlay)
 {
   Lock();
@@ -1480,7 +1494,6 @@ void cPixmapMemory::DrawEllipse(const cRect &Rect, tColor Color, int Quadrants)
 
 void cPixmapMemory::DrawSlope(const cRect &Rect, tColor Color, int Type)
 {
-  //TODO anti-aliasing?
   //TODO also simplify cBitmap::DrawSlope()
   Lock();
   bool upper    = Type & 0x01;
@@ -1492,28 +1505,87 @@ void cPixmapMemory::DrawSlope(const cRect &Rect, tColor Color, int Type)
   int y2 = Rect.Bottom();
   int w  = Rect.Width();
   int h  = Rect.Height();
+  bool AntiAliased = Setup.AntiAlias;
+  uint8_t intensity = 0;
+
   if (vertical) {
-     for (int y = y1; y <= y2; y++) {
-         double c = cos((y - y1) * M_PI / h);
+     if (upper)
+        DrawRectangle(cRect(x1, y1, w, 1), Color);
+     else
+        DrawRectangle(cRect(x1, y2, w, 1), Color);
+     for (int y = 1; y <= (y2 - y1) / 2; y++) {
+         double c = cos(y * M_PI / (y2 - y1));
+         if (AntiAliased) {
+            double wc = (w * c + (w & 1)) / 2;
+            intensity = 255 * fabs(wc - floor(wc));
+            }
          if (falling)
             c = -c;
-         int x = (x1 + x2) / 2 + int(w * c / 2);
-         if (upper && !falling || !upper && falling)
-            DrawRectangle(cRect(x1, y, x - x1 + 1, 1), Color);
-         else
-            DrawRectangle(cRect(x, y, x2 - x + 1, 1), Color);
+         int x = (x1 + x2 + w * c + 1) / 2;
+         if (upper && !falling || !upper && falling) {
+            if (AntiAliased) {
+               DrawRectangle(cRect(x1, y1 + y, x - x1, 1), Color);
+               DrawBlendedPixel(cPoint(x, y1 + y), Color, upper ? intensity : 255 - intensity);
+               DrawRectangle(cRect(x1, y2 - y, x2 - x, 1), Color);
+               DrawBlendedPixel(cPoint(x1 + x2 - x, y2 - y), Color, upper ? 255 - intensity : intensity);
+               }
+            else {
+               DrawRectangle(cRect(x1, y1 + y, x - x1 + 1, 1), Color);
+               DrawRectangle(cRect(x1, y2 - y, x2 - x + 1, 1), Color);
+               }
+            }
+         else {
+            if (AntiAliased) {
+               DrawRectangle(cRect(x + 1, y1 + y, x2 - x, 1), Color);
+               DrawBlendedPixel(cPoint(x, y1 + y), Color, falling ? intensity : 255 - intensity);
+               DrawRectangle(cRect(x1 + x2 - x + 1, y2 - y, x - x1, 1), Color);
+               DrawBlendedPixel(cPoint(x1 + x2 - x, y2 - y), Color, falling ? 255 - intensity : intensity);
+               }
+            else {
+               DrawRectangle(cRect(x, y1 + y, x2 - x + 1, 1), Color);
+               DrawRectangle(cRect(x1 + x2 - x, y2 - y, x - x1 + 1, 1), Color);
+               }
+            }
          }
      }
   else {
-     for (int x = x1; x <= x2; x++) {
-         double c = cos((x - x1) * M_PI / w);
+     if ((upper && !falling) || (!upper && falling))
+        DrawRectangle(cRect(x1, y1, 1, h), Color);
+     else
+        DrawRectangle(cRect(x2, y1, 1, h), Color);
+     for (int x = 1; x <= (x2 - x1) / 2; x++) {
+         double c = cos(x * M_PI / (x2 - x1));
+         if (AntiAliased) {
+            double hc = (h * c + (h & 1)) / 2;
+            intensity = 255 * fabs(hc - floor(hc));
+            }
          if (falling)
             c = -c;
-         int y = (y1 + y2) / 2 + int(h * c / 2);
-         if (upper)
-            DrawRectangle(cRect(x, y1, 1, y - y1 + 1), Color);
-         else
-            DrawRectangle(cRect(x, y, 1, y2 - y + 1), Color);
+         int y = (y1 + y2 + h * c + 1) / 2;
+         if (upper) {
+            if (AntiAliased) {
+               DrawRectangle(cRect(x1 + x, y1, 1, y - y1), Color);
+               DrawBlendedPixel(cPoint(x1 + x, y), Color, falling ? 255 - intensity : intensity);
+               DrawRectangle(cRect(x2 - x, y1, 1, y2 - y), Color); 
+               DrawBlendedPixel(cPoint(x2 - x, y1 + y2 - y), Color, falling ? intensity : 255 - intensity);
+               }
+            else {
+               DrawRectangle(cRect(x1 + x, y1, 1, y - y1 + 1), Color);
+               DrawRectangle(cRect(x2 - x, y1, 1, y2 - y + 1), Color);
+               }
+            }
+         else {
+            if (AntiAliased) {
+               DrawRectangle(cRect(x1 + x, y + 1, 1, y2 - y), Color);
+               DrawBlendedPixel(cPoint(x1 + x, y), Color, falling ? intensity : 255 - intensity);
+               DrawRectangle(cRect(x2 - x, y1 + y2 - y + 1, 1, y - y1), Color);
+               DrawBlendedPixel(cPoint(x2 - x, y1 + y2 - y), Color, falling ? 255 - intensity : intensity);
+               }
+            else {
+               DrawRectangle(cRect(x1 + x, y, 1, y2 - y + 1), Color);
+               DrawRectangle(cRect(x2 - x, y1 + y2 - y, 1, y - y1 + 1), Color);
+               }
+            }
          }
      }
   MarkDrawPortDirty(Rect);
diff --git a/osd.h b/osd.h
index 51b1adf9..eeb5496f 100644
--- a/osd.h
+++ b/osd.h
@@ -4,7 +4,7 @@
  * See the main source file 'vdr.c' for copyright information and
  * how to reach the author.
  *
- * $Id: osd.h 4.6 2019/05/24 21:28:35 kls Exp $
+ * $Id: osd.h 4.7 2020/09/29 14:09:26 kls Exp $
  */
 
 #ifndef __OSD_H
@@ -607,6 +607,10 @@ public:
        ///< a full 32 bit ARGB value. If the alpha value of Color is not 0xFF
        ///< (fully opaque), and this is the background pixmap (layer 0), the pixel is
        ///< alpha blended with the existing color at the given position in this pixmap.
+  virtual void DrawBlendedPixel(const cPoint &Point, tColor Color, uint8_t AlphaLayer = ALPHA_OPAQUE) { DrawPixel(Point, Color); }
+       ///< Like DrawPixel(), but with an additional AlphaLayer, and works on any
+       ///< pixmap, not only the background. The default implementation just calls
+       ///< DrawPixel(), ignoring AlphaLayer.
   virtual void DrawBitmap(const cPoint &Point, const cBitmap &Bitmap, tColor ColorFg = 0, tColor ColorBg = 0, bool Overlay = false) = 0;
        ///< Sets the pixels in the OSD with the data from the given
        ///< Bitmap, putting the upper left corner of the Bitmap at Point.
@@ -697,6 +701,7 @@ public:
   virtual void DrawImage(const cPoint &Point, const cImage &Image);
   virtual void DrawImage(const cPoint &Point, int ImageHandle);
   virtual void DrawPixel(const cPoint &Point, tColor Color);
+  virtual void DrawBlendedPixel(const cPoint &Point, tColor Color, uint8_t AlphaLayer = ALPHA_OPAQUE);
   virtual void DrawBitmap(const cPoint &Point, const cBitmap &Bitmap, tColor ColorFg = 0, tColor ColorBg = 0, bool Overlay = false);
   virtual void DrawText(const cPoint &Point, const char *s, tColor ColorFg, tColor ColorBg, const cFont *Font, int Width = 0, int Height = 0, int Alignment = taDefault);
   virtual void DrawRectangle(const cRect &Rect, tColor Color);