--- a/brewpanel/sdlgui.c Thu Nov 19 15:05:19 2015 +0100
+++ b/brewpanel/sdlgui.c Thu Nov 19 20:45:09 2015 +0100
@@ -495,6 +495,116 @@
/*
+ * SDL_Surface 32-bit circle-fill algorithm without using trig
+ *
+ * While I humbly call this "Celdecea's Method", odds are that the
+ * procedure has already been documented somewhere long ago. All of
+ * the circle-fill examples I came across utilized trig functions or
+ * scanning neighbor pixels. This algorithm identifies the width of
+ * a semi-circle at each pixel height and draws a scan-line covering
+ * that width.
+ *
+ * The code is not optimized but very fast, owing to the fact that it
+ * alters pixels in the provided surface directly rather than through
+ * function calls.
+ */
+void SDLGui_fill_circle(SDL_Surface *surface, int cx, int cy, int radius, Uint32 pixel)
+{
+ /*
+ * Note that there is more to altering the bitrate of this
+ * method than just changing this value. See how pixels are
+ * altered at the following web page for tips:
+ * http://www.libsdl.org/intro.en/usingvideo.html
+ */
+ static const int BPP = 4;
+ double r = (double)radius;
+ double dy;
+
+ for (dy = 1; dy <= r; dy += 1.0) {
+ /*
+ * This loop is unrolled a bit, only iterating through half of the
+ * height of the circle. The result is used to draw a scan line and
+ * its mirror image below it.
+ *
+ * The following formula has been simplified from our original. We
+ * are using half of the width of the circle because we are provided
+ * with a center and we need left/right coordinates.
+ */
+ double dx = floor(sqrt((2.0 * r * dy) - (dy * dy)));
+ int x = cx - dx;
+
+ // Grab a pointer to the left-most pixel for each half of the circle
+ Uint8 *target_pixel_a = (Uint8 *)surface->pixels + ((int)(cy + r - dy)) * surface->pitch + x * BPP;
+ Uint8 *target_pixel_b = (Uint8 *)surface->pixels + ((int)(cy - r + dy)) * surface->pitch + x * BPP;
+
+ for (; x <= cx + dx; x++) {
+ *(Uint32 *)target_pixel_a = pixel;
+ *(Uint32 *)target_pixel_b = pixel;
+ target_pixel_a += BPP;
+ target_pixel_b += BPP;
+ }
+ }
+}
+
+
+
+static void SDLGUI_DrawLEDRed(const SGOBJ *bdlg, int objnum)
+{
+ Uint32 color;
+
+ if (bdlg[objnum].state & SG_SELECTED) {
+ color = SDL_MapRGB(pSdlGuiScrn->format, 255, 64, 0);
+ } else {
+ color = SDL_MapRGB(pSdlGuiScrn->format, 128, 16, 0);
+ }
+ SDLGui_fill_circle(pSdlGuiScrn, bdlg[objnum].x, bdlg[objnum].y, bdlg[objnum].w, color);
+}
+
+
+
+static void SDLGUI_DrawLEDBlue(const SGOBJ *bdlg, int objnum)
+{
+ Uint32 color;
+
+ if (bdlg[objnum].state & SG_SELECTED) {
+ color = SDL_MapRGB(pSdlGuiScrn->format, 64, 160, 255);
+ } else {
+ color = SDL_MapRGB(pSdlGuiScrn->format, 16, 48, 112);
+ }
+ SDLGui_fill_circle(pSdlGuiScrn, bdlg[objnum].x, bdlg[objnum].y, bdlg[objnum].w, color);
+}
+
+
+
+static void SDLGUI_DrawLEDGreen(const SGOBJ *bdlg, int objnum)
+{
+ Uint32 color;
+
+ if (bdlg[objnum].state & SG_SELECTED) {
+ color = SDL_MapRGB(pSdlGuiScrn->format, 80, 240, 0);
+ } else {
+ color = SDL_MapRGB(pSdlGuiScrn->format, 32, 112, 0);
+ }
+ SDLGui_fill_circle(pSdlGuiScrn, bdlg[objnum].x, bdlg[objnum].y, bdlg[objnum].w, color);
+}
+
+
+
+static void SDLGUI_DrawLEDYellow(const SGOBJ *bdlg, int objnum)
+{
+ Uint32 color;
+
+ if (bdlg[objnum].state & SG_SELECTED) {
+ color = SDL_MapRGB(pSdlGuiScrn->format, 255, 255, 0);
+ } else {
+ color = SDL_MapRGB(pSdlGuiScrn->format, 160, 144, 0);
+ }
+ SDLGui_fill_circle(pSdlGuiScrn, bdlg[objnum].x, bdlg[objnum].y, bdlg[objnum].w, color);
+}
+
+
+
+/*
* Draw a whole dialog.
*/
void SDLGui_DrawDialog(const SGOBJ *dlg)
@@ -518,6 +628,18 @@
case SGBUTTON:
SDLGui_DrawButton(dlg, i);
break;
+ case SGLEDRED:
+ SDLGUI_DrawLEDRed(dlg, i);
+ break;
+ case SGLEDBLUE:
+ SDLGUI_DrawLEDBlue(dlg, i);
+ break;
+ case SGLEDGREEN:
+ SDLGUI_DrawLEDGreen(dlg, i);
+ break;
+ case SGLEDYELLOW:
+ SDLGUI_DrawLEDYellow(dlg, i);
+ break;
}
}
