Commonise GuiColorPanelHSV and GuiColorPanel logic and behavior (#370)

* transferred dragging GuiColorPanel outside bounds (#366) to GuiColorPanelHSV

* call GuiColorPanelHSV from inside GuiColorPanel, to eliminate code duplication

* comply with naming convention inside GuiColorPanel

src/raygui.h

@@ -3343,122 +3343,32 @@ int GuiListViewEx(Rectangle bounds, const char **text, int count, int *scrollInd
     return result;
 }
 
-// Color Panel control
+// Color Panel control - Color (RGBA) variant.
 int GuiColorPanel(Rectangle bounds, const char *text, Color *color)
 {
     int result = 0;
-    GuiState state = guiState;
-    Vector2 pickerSelector = { 0 };
-
-    const Color colWhite = { 255, 255, 255, 255 };
-    const Color colBlack = { 0, 0, 0, 255 };
 
     Vector3 vcolor = { (float)color->r/255.0f, (float)color->g/255.0f, (float)color->b/255.0f };
     Vector3 hsv = ConvertRGBtoHSV(vcolor);
+    Vector3 prevHsv = hsv; // workaround to see if GuiColorPanelHSV modifies the hsv.
 
-    pickerSelector.x = bounds.x + (float)hsv.y*bounds.width;            // HSV: Saturation
-    pickerSelector.y = bounds.y + (1.0f - (float)hsv.z)*bounds.height;  // HSV: Value
-
-    Vector3 maxHue = { hsv.x, 1.0f, 1.0f };
-    Vector3 rgbHue = ConvertHSVtoRGB(maxHue);
-    Color maxHueCol = { (unsigned char)(255.0f*rgbHue.x),
-                      (unsigned char)(255.0f*rgbHue.y),
-                      (unsigned char)(255.0f*rgbHue.z), 255 };
-
-    // Update control
-    //--------------------------------------------------------------------
-    if ((state != STATE_DISABLED) && !guiLocked)
-    {
-        Vector2 mousePoint = GetMousePosition();
-
-        if (guiSliderDragging)
-        {
-            if (IsMouseButtonDown(MOUSE_LEFT_BUTTON))
-            {
-                if (CHECK_BOUNDS_ID(bounds, guiSliderActive))
-                {
-                    pickerSelector = mousePoint;
-
-                    if (pickerSelector.x < bounds.x) pickerSelector.x = bounds.x;
-                    if (pickerSelector.x > bounds.x + bounds.width) pickerSelector.x = bounds.x + bounds.width;
-                    if (pickerSelector.y < bounds.y) pickerSelector.y = bounds.y;
-                    if (pickerSelector.y > bounds.y + bounds.height) pickerSelector.y = bounds.y + bounds.height;
-
-                    // Calculate color from picker
-                    Vector2 colorPick = { pickerSelector.x - bounds.x, pickerSelector.y - bounds.y };
-
-                    colorPick.x /= (float)bounds.width;     // Get normalized value on x
-                    colorPick.y /= (float)bounds.height;    // Get normalized value on y
-
-                    hsv.y = colorPick.x;
-                    hsv.z = 1.0f - colorPick.y;
-
-                    Vector3 rgb = ConvertHSVtoRGB(hsv);
-
-                    // NOTE: Vector3ToColor() only available on raylib 1.8.1
-                    *color = RAYGUI_CLITERAL(Color){ (unsigned char)(255.0f*rgb.x),
-                                     (unsigned char)(255.0f*rgb.y),
-                                     (unsigned char)(255.0f*rgb.z),
-                                     (unsigned char)(255.0f*(float)color->a/255.0f) };
-                }
-            }
-            else
-            {
-                guiSliderDragging = false;
-                guiSliderActive = RAYGUI_CLITERAL(Rectangle){ 0, 0, 0, 0 };
-            }
-        }
-        else if (CheckCollisionPointRec(mousePoint, bounds))
-        {
-            if (IsMouseButtonDown(MOUSE_LEFT_BUTTON))
-            {
-                state = STATE_PRESSED;
-                guiSliderDragging = true;
-                guiSliderActive = bounds;
-                pickerSelector = mousePoint;
-
-                // Calculate color from picker
-                Vector2 colorPick = { pickerSelector.x - bounds.x, pickerSelector.y - bounds.y };
-
-                colorPick.x /= (float)bounds.width;     // Get normalized value on x
-                colorPick.y /= (float)bounds.height;    // Get normalized value on y
-
-                hsv.y = colorPick.x;
-                hsv.z = 1.0f - colorPick.y;
-
-                Vector3 rgb = ConvertHSVtoRGB(hsv);
+    GuiColorPanelHSV(bounds, text, &hsv);
 
-                // NOTE: Vector3ToColor() only available on raylib 1.8.1
-                *color = RAYGUI_CLITERAL(Color){ (unsigned char)(255.0f*rgb.x),
-                                 (unsigned char)(255.0f*rgb.y),
-                                 (unsigned char)(255.0f*rgb.z),
-                                 (unsigned char)(255.0f*(float)color->a/255.0f) };
-
-            }
-            else state = STATE_FOCUSED;
-        }
-    }
-    //--------------------------------------------------------------------
-
-    // Draw control
-    //--------------------------------------------------------------------
-    if (state != STATE_DISABLED)
+    // Check if the hsv was changed, only then change the color.
+    // This is necessary, because the Color->HSV->Color conversion has precision errors.
+    // Thus the assignment from HSV to Color should only be made, if the HSV has a new user-entered value.
+    // Otherwise GuiColorPanel would often modify it's color without user input.
+    // TODO: GuiColorPanelHSV could return 1 if the slider was dragged, to simplify this check.
+    if (hsv.x != prevHsv.x || hsv.y != prevHsv.y || hsv.z != prevHsv.z)
     {
-        DrawRectangleGradientEx(bounds, Fade(colWhite, guiAlpha), Fade(colWhite, guiAlpha), Fade(maxHueCol, guiAlpha), Fade(maxHueCol, guiAlpha));
-        DrawRectangleGradientEx(bounds, Fade(colBlack, 0), Fade(colBlack, guiAlpha), Fade(colBlack, guiAlpha), Fade(colBlack, 0));
+        Vector3 rgb = ConvertHSVtoRGB(hsv);
 
-        // Draw color picker: selector
-        Rectangle selector = { pickerSelector.x - GuiGetStyle(COLORPICKER, COLOR_SELECTOR_SIZE)/2, pickerSelector.y - GuiGetStyle(COLORPICKER, COLOR_SELECTOR_SIZE)/2, (float)GuiGetStyle(COLORPICKER, COLOR_SELECTOR_SIZE), (float)GuiGetStyle(COLORPICKER, COLOR_SELECTOR_SIZE) };
-        GuiDrawRectangle(selector, 0, BLANK, colWhite);
-    }
-    else
-    {
-        DrawRectangleGradientEx(bounds, Fade(Fade(GetColor(GuiGetStyle(COLORPICKER, BASE_COLOR_DISABLED)), 0.1f), guiAlpha), Fade(Fade(colBlack, 0.6f), guiAlpha), Fade(Fade(colBlack, 0.6f), guiAlpha), Fade(Fade(GetColor(GuiGetStyle(COLORPICKER, BORDER_COLOR_DISABLED)), 0.6f), guiAlpha));
+        // NOTE: Vector3ToColor() only available on raylib 1.8.1
+        *color = RAYGUI_CLITERAL(Color){ (unsigned char)(255.0f*rgb.x),
+                            (unsigned char)(255.0f*rgb.y),
+                            (unsigned char)(255.0f*rgb.z),
+                            color->a };
     }
-
-    GuiDrawRectangle(bounds, GuiGetStyle(COLORPICKER, BORDER_WIDTH), GetColor(GuiGetStyle(COLORPICKER, BORDER + state*3)), BLANK);
-    //--------------------------------------------------------------------
-
     return result;
 }
 
@@ -3697,8 +3607,7 @@ int GuiColorPickerHSV(Rectangle bounds, const char *text, Vector3 *colorHsv)
     return result;
 }
 
-// Color Panel control, returns HSV color value in *colorHsv.
-// Used by GuiColorPickerHSV()
+// Color Panel control - HSV variant.
 int GuiColorPanelHSV(Rectangle bounds, const char *text, Vector3 *colorHsv)
 {
     int result = 0;
@@ -3719,15 +3628,47 @@ int GuiColorPanelHSV(Rectangle bounds, const char *text, Vector3 *colorHsv)
 
     // Update control
     //--------------------------------------------------------------------
-    if ((state != STATE_DISABLED) && !guiLocked && !guiSliderDragging)
+    if ((state != STATE_DISABLED) && !guiLocked)
     {
         Vector2 mousePoint = GetMousePosition();
 
-        if (CheckCollisionPointRec(mousePoint, bounds))
+        if (guiSliderDragging)
+        {
+            if (IsMouseButtonDown(MOUSE_LEFT_BUTTON))
+            {
+                if (CHECK_BOUNDS_ID(bounds, guiSliderActive))
+                {
+                    pickerSelector = mousePoint;
+
+                    if (pickerSelector.x < bounds.x) pickerSelector.x = bounds.x;
+                    if (pickerSelector.x > bounds.x + bounds.width) pickerSelector.x = bounds.x + bounds.width;
+                    if (pickerSelector.y < bounds.y) pickerSelector.y = bounds.y;
+                    if (pickerSelector.y > bounds.y + bounds.height) pickerSelector.y = bounds.y + bounds.height;
+
+                    // Calculate color from picker
+                    Vector2 colorPick = { pickerSelector.x - bounds.x, pickerSelector.y - bounds.y };
+
+                    colorPick.x /= (float)bounds.width;     // Get normalized value on x
+                    colorPick.y /= (float)bounds.height;    // Get normalized value on y
+
+                    colorHsv->y = colorPick.x;
+                    colorHsv->z = 1.0f - colorPick.y;
+
+                }
+            }
+            else
+            {
+                guiSliderDragging = false;
+                guiSliderActive = RAYGUI_CLITERAL(Rectangle){ 0, 0, 0, 0 };
+            }
+        }
+        else if (CheckCollisionPointRec(mousePoint, bounds))
         {
             if (IsMouseButtonDown(MOUSE_LEFT_BUTTON))
             {
                 state = STATE_PRESSED;
+                guiSliderDragging = true;
+                guiSliderActive = bounds;
                 pickerSelector = mousePoint;
 
                 // Calculate color from picker
@@ -3766,6 +3707,7 @@ int GuiColorPanelHSV(Rectangle bounds, const char *text, Vector3 *colorHsv)
     return result;
 }
 
+
 // Message Box control
 int GuiMessageBox(Rectangle bounds, const char *title, const char *message, const char *buttons)
 {