Merge pull request #3192 from pygame-community/revert-3140-draw.aalin…

…e_width

Revert 3140 draw.aaline width

buildconfig/stubs/pygame/draw.pyi

@@ -82,7 +82,6 @@ def aaline(
     color: ColorLike,
     start_pos: Point,
     end_pos: Point,
-    width: int = 1,
 ) -> Rect: ...
 def aalines(
     surface: Surface,

docs/reST/ref/code_examples/draw_module_example.py

@@ -30,10 +30,6 @@
     # 5 pixels wide. Uses (r, g, b) color - medium sea green.
     pygame.draw.line(screen, (60, 179, 113), [0, 0], [50, 30], 5)
 
-    # Draw on the screen a green antialiased line from (0, 25) to (50, 55)
-    # 5 pixels wide. Uses (r, g, b) color - medium sea green.
-    pygame.draw.aaline(screen, (60, 179, 113), [0, 25], [50, 55], 5)
-
     # Draw on the screen a green line from (0, 50) to (50, 80)
     # Because it is an antialiased line, it is 1 pixel wide.
     # Uses (r, g, b) color - medium sea green.

docs/reST/ref/draw.rst

@@ -451,10 +451,72 @@ object around the draw calls (see :func:`pygame.Surface.lock` and
 
    | :sl:`draw a straight antialiased line`
    | :sg:`aaline(surface, color, start_pos, end_pos) -> Rect`
-     :sg:`aaline(surface, color, start_pos, end_pos, width=1) -> Rect`
 
-   Draws a straight antialiased line on the given surface. There are no endcaps.
-   For thick lines the ends are squared off.
+   Draws a straight antialiased line on the given surface.
+
+   The line has a thickness of one pixel and the endpoints have a height and
+   width of one pixel each.
+
+   The way a line and its endpoints are drawn:
+      If both endpoints are equal, only a single pixel is drawn (after
+      rounding floats to nearest integer).
+
+      Otherwise if the line is not steep (i.e. if the length along the x-axis
+      is greater than the height along the y-axis):
+
+         For each endpoint:
+
+            If ``x``, the endpoint's x-coordinate, is a whole number find
+            which pixels would be covered by it and draw them.
+
+            Otherwise:
+
+               Calculate the position of the nearest point with a whole number
+               for its x-coordinate, when extending the line past the
+               endpoint.
+
+               Find which pixels would be covered and how much by that point.
+
+               If the endpoint is the left one, multiply the coverage by (1 -
+               the decimal part of ``x``).
+
+               Otherwise multiply the coverage by the decimal part of ``x``.
+
+               Then draw those pixels.
+
+               *e.g.:*
+                  | The left endpoint of the line ``((1, 1.3), (5, 3))`` would
+                    cover 70% of the pixel ``(1, 1)`` and 30% of the pixel
+                    ``(1, 2)`` while the right one would cover 100% of the
+                    pixel ``(5, 3)``.
+                  | The left endpoint of the line ``((1.2, 1.4), (4.6, 3.1))``
+                    would cover 56% *(i.e. 0.8 * 70%)* of the pixel ``(1, 1)``
+                    and 24% *(i.e. 0.8 * 30%)* of the pixel ``(1, 2)`` while
+                    the right one would cover 42% *(i.e. 0.6 * 70%)* of the
+                    pixel ``(5, 3)`` and 18% *(i.e. 0.6 * 30%)* of the pixel
+                    ``(5, 4)`` while the right
+
+         Then for each point between the endpoints, along the line, whose
+         x-coordinate is a whole number:
+
+            Find which pixels would be covered and how much by that point and
+            draw them.
+
+            *e.g.:*
+               | The points along the line ``((1, 1), (4, 2.5))`` would be
+                 ``(2, 1.5)`` and ``(3, 2)`` and would cover 50% of the pixel
+                 ``(2, 1)``, 50% of the pixel ``(2, 2)`` and 100% of the pixel
+                 ``(3, 2)``.
+               | The points along the line ``((1.2, 1.4), (4.6, 3.1))`` would
+                 be ``(2, 1.8)`` (covering 20% of the pixel ``(2, 1)`` and 80%
+                 of the pixel ``(2, 2)``), ``(3, 2.3)`` (covering 70% of the
+                 pixel ``(3, 2)`` and 30% of the pixel ``(3, 3)``) and ``(4,
+                 2.8)`` (covering 20% of the pixel ``(2, 1)`` and 80% of the
+                 pixel ``(2, 2)``)
+
+      Otherwise do the same for steep lines as for non-steep lines except
+      along the y-axis instead of the x-axis (using ``y`` instead of ``x``,
+      top instead of left and bottom instead of right).
 
    .. note::
       Regarding float values for coordinates, a point with coordinate
@@ -476,11 +538,6 @@ object around the draw calls (see :func:`pygame.Surface.lock` and
    :param end_pos: end position of the line, (x, y)
    :type end_pos: tuple(int or float, int or float) or
       list(int or float, int or float) or Vector2(int or float, int or float)
-   :param int width: (optional) used for line thickness
-
-         | if width >= 1, used for line thickness (default is 1)
-         | if width < 1, nothing will be drawn
-         |
 
    :returns: a rect bounding the changed pixels, if nothing is drawn the
       bounding rect's position will be the ``start_pos`` parameter value (float
@@ -493,7 +550,6 @@ object around the draw calls (see :func:`pygame.Surface.lock` and
    .. versionchangedold:: 2.0.0 Added support for keyword arguments.
    .. versionchanged:: 2.4.0 Removed deprecated 'blend' argument
    .. versionchanged:: 2.5.0 ``blend`` argument readded for backcompat, but will always raise a deprecation exception when used
-   .. versionchanged:: 2.5.2 Added line width
 
    .. ## pygame.draw.aaline ##
 

src_c/doc/draw_doc.h

@@ -8,5 +8,5 @@
 #define DOC_DRAW_ARC "arc(surface, color, rect, start_angle, stop_angle) -> Rect\narc(surface, color, rect, start_angle, stop_angle, width=1) -> Rect\ndraw an elliptical arc"
 #define DOC_DRAW_LINE "line(surface, color, start_pos, end_pos) -> Rect\nline(surface, color, start_pos, end_pos, width=1) -> Rect\ndraw a straight line"
 #define DOC_DRAW_LINES "lines(surface, color, closed, points) -> Rect\nlines(surface, color, closed, points, width=1) -> Rect\ndraw multiple contiguous straight line segments"
-#define DOC_DRAW_AALINE "aaline(surface, color, start_pos, end_pos) -> Rect\naaline(surface, color, start_pos, end_pos, width=1) -> Rect\ndraw a straight antialiased line"
+#define DOC_DRAW_AALINE "aaline(surface, color, start_pos, end_pos) -> Rect\ndraw a straight antialiased line"
 #define DOC_DRAW_AALINES "aalines(surface, color, closed, points) -> Rect\ndraw multiple contiguous straight antialiased line segments"

src_c/draw.c

@@ -44,10 +44,6 @@ draw_line_width(SDL_Surface *surf, Uint32 color, int x1, int y1, int x2,
 static void
 draw_line(SDL_Surface *surf, int x1, int y1, int x2, int y2, Uint32 color,
           int *drawn_area);
-void
-line_width_corners(float from_x, float from_y, float to_x, float to_y,
-                   int width, float *x1, float *y1, float *x2, float *y2,
-                   float *x3, float *y3, float *x4, float *y4);
 static void
 draw_aaline(SDL_Surface *surf, Uint32 color, float startx, float starty,
             float endx, float endy, int *drawn_area,
@@ -119,17 +115,16 @@ aaline(PyObject *self, PyObject *arg, PyObject *kwargs)
     PyObject *colorobj, *start, *end;
     SDL_Surface *surf = NULL;
     float startx, starty, endx, endy;
-    int width = 1; /* Default width. */
     PyObject *blend = NULL;
     int drawn_area[4] = {INT_MAX, INT_MAX, INT_MIN,
                          INT_MIN}; /* Used to store bounding box values */
     Uint32 color;
-    static char *keywords[] = {"surface", "color", "start_pos", "end_pos",
-                               "width",   "blend", NULL};
+    static char *keywords[] = {"surface", "color", "start_pos",
+                               "end_pos", "blend", NULL};
 
-    if (!PyArg_ParseTupleAndKeywords(arg, kwargs, "O!OOO|iO", keywords,
+    if (!PyArg_ParseTupleAndKeywords(arg, kwargs, "O!OOO|O", keywords,
                                      &pgSurface_Type, &surfobj, &colorobj,
-                                     &start, &end, &width, &blend)) {
+                                     &start, &end, &blend)) {
         return NULL; /* Exception already set. */
     }
 
@@ -162,27 +157,11 @@ aaline(PyObject *self, PyObject *arg, PyObject *kwargs)
         return RAISE(PyExc_TypeError, "invalid end_pos argument");
     }
 
-    if (width < 1) {
-        return pgRect_New4((int)startx, (int)starty, 0, 0);
-    }
-
     if (!pgSurface_Lock(surfobj)) {
         return RAISE(PyExc_RuntimeError, "error locking surface");
     }
 
-    if (width > 1) {
-        float x1, y1, x2, y2, x3, y3, x4, y4;
-        line_width_corners(startx, starty, endx, endy, width, &x1, &y1, &x2,
-                           &y2, &x3, &y3, &x4, &y4);
-        draw_line_width(surf, color, (int)startx, (int)starty, (int)endx,
-                        (int)endy, width, drawn_area);
-        draw_aaline(surf, color, x1, y1, x2, y2, drawn_area, 0, 0, 0);
-        draw_aaline(surf, color, x3, y3, x4, y4, drawn_area, 0, 0, 0);
-    }
-    else {
-        draw_aaline(surf, color, startx, starty, endx, endy, drawn_area, 0, 0,
-                    0);
-    }
+    draw_aaline(surf, color, startx, starty, endx, endy, drawn_area, 0, 0, 0);
 
     if (!pgSurface_Unlock(surfobj)) {
         return RAISE(PyExc_RuntimeError, "error unlocking surface");
@@ -1866,39 +1845,6 @@ draw_line_width(SDL_Surface *surf, Uint32 color, int x1, int y1, int x2,
     }
 }
 
-// Calculates 4 points, representing corners of draw_line_width()
-// first two points assemble left line and second two - right line
-void
-line_width_corners(float from_x, float from_y, float to_x, float to_y,
-                   int width, float *x1, float *y1, float *x2, float *y2,
-                   float *x3, float *y3, float *x4, float *y4)
-{
-    float aa_width = (float)width / 2;
-    float extra_width = (1.0f - (width % 2)) / 2;
-    int steep = fabs(to_x - from_x) <= fabs(to_y - from_y);
-
-    if (steep) {
-        *x1 = from_x + extra_width + aa_width;
-        *y1 = from_y;
-        *x2 = to_x + extra_width + aa_width;
-        *y2 = to_y;
-        *x3 = from_x + extra_width - aa_width;
-        *y3 = from_y;
-        *x4 = to_x + extra_width - aa_width;
-        *y4 = to_y;
-    }
-    else {
-        *x1 = from_x;
-        *y1 = from_y + extra_width + aa_width;
-        *x2 = to_x;
-        *y2 = to_y + extra_width + aa_width;
-        *x3 = from_x;
-        *y3 = from_y + extra_width - aa_width;
-        *x4 = to_x;
-        *y4 = to_y + extra_width - aa_width;
-    }
-}
-
 /* Algorithm modified from
  * https://rosettacode.org/wiki/Bitmap/Bresenham%27s_line_algorithm
  */