widgets.drag.go

package imgui

import (
	"fmt"
	"math"
	"reflect"
	"strconv"
)

// Widgets: Drag Sliders
//   - CTRL+Click on any drag box to turn them into an input box. Manually input values aren't clamped and can go off-bounds.
//   - For all the Float2/Float3/Float4/Int2/Int3/Int4 versions of every functions, note that a 'v float[X]' function argument is the same as 'float* v', the array syntax is just a way to document the number of elements that are expected to be accessible. You can pass address of your first element out of a contiguous set, e.g. &myvector.x
//   - Adjust format string to decorate the value with a prefix, a suffix, or adapt the editing and display precision e.g. "%.3f" -> 1.234; "%5.2 secs" -> 01.23 secs; "Biscuit: %.0f" -> Biscuit: 1; etc.
//   - Format string may also be set to NULL or use the default format ("%f" or "%d").
//   - Speed are per-pixel of mouse movement (v_speed=0.2: mouse needs to move by 5 pixels to increase value by 1). For gamepad/keyboard navigation, minimum speed is Max(v_speed, minimum_step_at_given_precision).
//   - Use v_min < v_max to clamp edits to given limits. Note that CTRL+Click manual input can override those limits.
//   - Use v_max/*= m*/,same with v_min = -FLT_MAX / INT_MIN to a clamping to a minimum.
//   - We use the same sets of flags for DragXXX() and SliderXXX() functions as the features are the same and it makes it easier to swap them.
//   - Legacy: Pre-1.78 there are DragXXX() function signatures that takes a final `power float=1.0' argument instead of the `ImGuiSliderFlags flags=0' argument.
//     If you get a warning converting a to float ImGuiSliderFlags, read https://github.com/ocornut/imgui/issues/3361
func DragFloat(label string, v *float, v_speed float /*= 0*/, v_min float /*= 0*/, v_max float /*= 0*/, format string /*= "%.3f"*/, flags ImGuiSliderFlags) bool {
	return DragScalar(label, ImGuiDataType_Float, v, v_speed, &v_min, &v_max, format, flags)
}

func DragFloat2(label string, v *[2]float, v_speed float /*= 0*/, v_min float /*= 0*/, v_max float /*= 0*/, format string /*= "%.3f"*/, flags ImGuiSliderFlags) bool {
	return DragScalarFloats(label, ImGuiDataType_Float, v[:], v_speed, &v_min, &v_max, format, flags)
}

func DragFloat3(label string, v *[3]float, v_speed float /*= 0*/, v_min float /*= 0*/, v_max float /*= 0*/, format string /*= "%.3f"*/, flags ImGuiSliderFlags) bool {
	return DragScalarFloats(label, ImGuiDataType_Float, v[:], v_speed, &v_min, &v_max, format, flags)
}

func DragFloat4(label string, v *[4]float, v_speed float /*= 0*/, v_min float /*= 0*/, v_max float /*= 0*/, format string /*= "%.3f"*/, flags ImGuiSliderFlags) bool {
	return DragScalarFloats(label, ImGuiDataType_Float, v[:], v_speed, &v_min, &v_max, format, flags)
}

// NB: You likely want to specify the ImGuiSliderFlags_AlwaysClamp when using this.
func DragFloatRange2(label string, v_current_min *float, v_current_max *float, v_speed float /*= 0*/, v_min float /*= 0*/, v_max float /*= 0*/, format string /*= "*/, format_max string, flags ImGuiSliderFlags) bool {
	var window = GetCurrentWindow()
	if window.SkipItems {
		return false
	}

	var g = GImGui
	PushString(label)
	BeginGroup()
	PushMultiItemsWidths(2, CalcItemWidth())

	var min_min = v_min
	if v_min >= v_max {
		min_min = -FLT_MAX
	}
	var min_max = ImMin(v_max, *v_current_max)
	if v_min >= v_max {
		min_max = *v_current_max
	}
	var min_flags = flags
	if min_min == min_max {
		min_flags |= ImGuiSliderFlags_ReadOnly
	}
	var value_changed = DragScalar("##min", ImGuiDataType_Float, v_current_min, v_speed, &min_min, &min_max, format, min_flags)
	PopItemWidth()
	SameLine(0, g.Style.ItemInnerSpacing.x)

	var max_min = ImMax(v_min, *v_current_min)
	if v_min >= v_max {
		max_min = *v_current_min
	}
	var max_max = v_max
	if v_min >= v_max {
		max_max = FLT_MAX
	}
	var max_flags = flags
	if max_min == max_max {
		max_flags |= ImGuiSliderFlags_ReadOnly
	}
	value_changed = DragScalar("##max", ImGuiDataType_Float, v_current_max, v_speed, &max_min, &max_max, format, max_flags) || value_changed
	PopItemWidth()
	SameLine(0, g.Style.ItemInnerSpacing.x)

	TextEx(label, 0)
	EndGroup()
	PopID()

	return value_changed
}

func DragInt(label string, v *int, v_speed float /*= 0*/, v_min int /*= 0*/, v_max int /*= 0*/, format string /*= "%d"*/, flags ImGuiSliderFlags) bool {
	return DragScalarInt(label, ImGuiDataType_S32, v, v_speed, &v_min, &v_max, format, flags)
}

func DragInt2(label string, v [2]int, v_speed float /*= 0*/, v_min int /*= 0*/, v_max int /*= 0*/, format string /*= "%d"*/, flags ImGuiSliderFlags) bool {
	return DragScalarInts(label, ImGuiDataType_S32, v[:], v_speed, &v_min, &v_max, format, flags)
}
func DragInt3(label string, v [3]int, v_speed float /*= 0*/, v_min int /*= 0*/, v_max int /*= 0*/, format string /*= "%d"*/, flags ImGuiSliderFlags) bool {
	return DragScalarInts(label, ImGuiDataType_S32, v[:], v_speed, &v_min, &v_max, format, flags)
}
func DragInt4(label string, v [4]int, v_speed float /*= 0*/, v_min int /*= 0*/, v_max int /*= 0*/, format string /*= "%d"*/, flags ImGuiSliderFlags) bool {
	return DragScalarInts(label, ImGuiDataType_S32, v[:], v_speed, &v_min, &v_max, format, flags)
}
func DragIntRange2(label string, v_current_min *int, v_current_max *int, v_speed float /*= 0*/, v_min int /*= 0*/, v_max int /*= 0*/, format string /*= "*/, format_max string, flags ImGuiSliderFlags) bool {
	var window = GetCurrentWindow()
	if window.SkipItems {
		return false
	}

	var g = GImGui
	PushString(label)
	BeginGroup()
	PushMultiItemsWidths(2, CalcItemWidth())

	var min_min = v_min
	if v_min >= v_max {
		min_min = math.MinInt32
	}
	var min_max = ImMinInt(v_max, *v_current_max)
	if v_min >= v_max {
		min_max = *v_current_max
	}
	var min_flags = flags
	if min_min == min_max {
		min_flags |= ImGuiSliderFlags_ReadOnly
	}
	var value_changed = DragScalar("##min", ImGuiDataType_S32, v_current_min, v_speed, &min_min, &min_max, format, min_flags)
	PopItemWidth()
	SameLine(0, g.Style.ItemInnerSpacing.x)

	var max_min = ImMaxInt(v_min, *v_current_min)
	if v_min >= v_max {
		max_min = *v_current_min
	}
	var max_max = v_max
	if v_min >= v_max {
		max_max = INT_MAX
	}
	var max_flags = flags
	if max_min == max_max {
		max_flags |= ImGuiSliderFlags_ReadOnly
	}
	value_changed = DragScalar("##max", ImGuiDataType_S32, v_current_max, v_speed, &max_min, &max_max, format, max_flags) || value_changed
	PopItemWidth()
	SameLine(0, g.Style.ItemInnerSpacing.x)

	TextEx(label, 0)
	EndGroup()
	PopID()

	return value_changed
}

func GetMinimumStepAtDecimalPrecision(decimal_precision int) float {
	var min_steps = [10]float{1.0, 0.1, 0.01, 0.001, 0.0001, 0.00001, 0.000001, 0.0000001, 0.00000001, 0.000000001}
	if decimal_precision < 0 {
		return FLT_MIN
	}
	if decimal_precision < int(len(min_steps)) {
		return min_steps[decimal_precision]
	} else {
		return ImPow(10, float(-decimal_precision))
	}
}

// Note: p_data, p_min and p_max are _pointers_ to a memory address holding the data. For a Drag widget, p_min and p_max are optional.
// Read code of e.g. DragFloat(), DragInt() etc. or examples in 'Demo.Widgets.Data Types' to understand how to use this function directly.
func DragScalar(label string, data_type ImGuiDataType, p_data any, v_speed float /*= 0*/, p_min any /*= L*/, p_max any /*= L*/, format string, flags ImGuiSliderFlags) bool {
	var window = GetCurrentWindow()
	if window.SkipItems {
		return false
	}

	var g = GImGui
	var style = g.Style
	var id = window.GetIDs(label)
	var w = CalcItemWidth()

	var label_size = CalcTextSize(label, true, -1)
	var frame_bb = ImRect{window.DC.CursorPos, window.DC.CursorPos.Add(ImVec2{w, label_size.y + style.FramePadding.y*2.0})}

	var padding float
	if label_size.x > 0.0 {
		padding = style.ItemInnerSpacing.x + label_size.x
	}

	var total_bb = ImRect{frame_bb.Min, frame_bb.Max.Add(ImVec2{padding, 0.0})}

	var temp_input_allowed = (flags & ImGuiSliderFlags_NoInput) == 0
	ItemSizeRect(&total_bb, style.FramePadding.y)

	var inputable_flags ImGuiItemFlags
	if temp_input_allowed {
		inputable_flags = ImGuiItemFlags_Inputable
	}

	if !ItemAdd(&total_bb, id, &frame_bb, inputable_flags) {
		return false
	}

	// Default format string when passing nil
	if format == "" {
		format = DataTypeGetInfo(data_type).PrintFmt
	}

	// Tabbing or CTRL-clicking on Drag turns it into an InputText
	var hovered = ItemHoverable(&frame_bb, id)
	var temp_input_is_active = temp_input_allowed && TempInputIsActive(id)
	if !temp_input_is_active {
		var focus_requested = temp_input_allowed && (g.LastItemData.StatusFlags&ImGuiItemStatusFlags_Focused) != 0
		var clicked = (hovered && g.IO.MouseClicked[0])
		var double_clicked = (hovered && g.IO.MouseDoubleClicked[0])
		if focus_requested || clicked || double_clicked || g.NavActivateId == id || g.NavInputId == id {
			SetActiveID(id, window)
			SetFocusID(id, window)
			FocusWindow(window)
			g.ActiveIdUsingNavDirMask = (1 << ImGuiDir_Left) | (1 << ImGuiDir_Right)
			if temp_input_allowed && (focus_requested || (clicked && g.IO.KeyCtrl) || double_clicked || g.NavInputId == id) {
				temp_input_is_active = true
			}
		}
		// Experimental: simple click (without moving) turns Drag into an InputText
		// FIXME: Currently polling ImGuiConfigFlags_IsTouchScreen, may either poll an hypothetical ImGuiBackendFlags_HasKeyboard and/or an explicit drag settings.
		if g.IO.ConfigDragClickToInputText && temp_input_allowed && !temp_input_is_active {
			if g.ActiveId == id && hovered && g.IO.MouseReleased[0] && !IsMouseDragPastThreshold(0, g.IO.MouseDragThreshold*DRAG_MOUSE_THRESHOLD_FACTOR) {
				g.NavInputId = id
				temp_input_is_active = true
			}
		}
	}

	if temp_input_is_active {
		// Only clamp CTRL+Click input when ImGuiSliderFlags_AlwaysClamp is set
		var is_clamp_input = (flags&ImGuiSliderFlags_AlwaysClamp) != 0 && (p_min == nil || p_max == nil || DataTypeCompare(data_type, p_min, p_max) < 0)

		var x, y any
		if is_clamp_input {
			x, y = p_min, p_max
		}

		return TempInputScalar(&frame_bb, id, label, data_type, p_data, format, x, y)
	}

	var c = ImGuiCol_FrameBg
	switch {
	case g.ActiveId == id:
		c = ImGuiCol_FrameBgActive
	case hovered:
		c = ImGuiCol_FrameBgHovered
	}

	// Draw frame
	var frame_col = GetColorU32FromID(c, 1)
	RenderNavHighlight(&frame_bb, id, 0)
	RenderFrame(frame_bb.Min, frame_bb.Max, frame_col, true, style.FrameRounding)

	// Drag behavior
	var value_changed = DragBehavior(id, data_type, p_data, v_speed, p_min, p_max, format, flags)
	if value_changed {
		MarkItemEdited(id)
	}

	// Display value using user-provided display format so user can add prefix/suffix/decorations to the value.
	p_data_val := reflect.ValueOf(p_data).Elem() // get actual value of the interface, not a pointer
	var value_buf = fmt.Sprintf(format, p_data_val)
	if g.LogEnabled {
		LogSetNextTextDecoration("{", "}")
	}
	RenderTextClipped(&frame_bb.Min, &frame_bb.Max, value_buf, nil, &ImVec2{0.5, 0.5}, nil)

	if label_size.x > 0.0 {
		RenderText(ImVec2{frame_bb.Max.x + style.ItemInnerSpacing.x, frame_bb.Min.y + style.FramePadding.y}, label, true)
	}

	return value_changed
}

func DragScalarFloat(label string, data_type ImGuiDataType, p_data *float, v_speed float /*= 0*/, p_min *float /*= L*/, p_max *float /*= L*/, format string, flags ImGuiSliderFlags) bool {
	var window = GetCurrentWindow()
	if window.SkipItems {
		return false
	}

	var g = GImGui
	var value_changed = false
	BeginGroup()
	PushString(label)
	PushMultiItemsWidths(1, CalcItemWidth())
	value_changed = DragScalar("", data_type, p_data, v_speed, p_min, p_max, format, flags) || value_changed
	PopItemWidth()
	PopID()

	SameLine(0, g.Style.ItemInnerSpacing.x)
	TextEx(label, 0)

	EndGroup()
	return value_changed
}

func DragScalarFloats(label string, data_type ImGuiDataType, p_data []float, v_speed float /*= 0*/, p_min *float /*= L*/, p_max *float /*= L*/, format string, flags ImGuiSliderFlags) bool {
	var window = GetCurrentWindow()
	if window.SkipItems {
		return false
	}

	var g = GImGui
	var value_changed = false
	BeginGroup()
	PushString(label)
	PushMultiItemsWidths(int(len(p_data)), CalcItemWidth())
	for i := range p_data {
		PushID(int(i))
		if i > 0 {
			SameLine(0, g.Style.ItemInnerSpacing.x)
		}
		value_changed = DragScalar("", data_type, &p_data[i], v_speed, p_min, p_max, format, flags) || value_changed
		PopID()
		PopItemWidth()
	}
	PopID()

	SameLine(0, g.Style.ItemInnerSpacing.x)
	TextEx(label, 0)

	EndGroup()
	return value_changed
}

func DragScalarInt(label string, data_type ImGuiDataType, p_data *int, v_speed float /*= 0*/, p_min *int /*= L*/, p_max *int /*= L*/, format string, flags ImGuiSliderFlags) bool {
	var window = GetCurrentWindow()
	if window.SkipItems {
		return false
	}

	var g = GImGui
	var value_changed = false
	BeginGroup()
	PushString(label)
	PushMultiItemsWidths(1, CalcItemWidth())
	value_changed = DragScalar("", data_type, p_data, v_speed, p_min, p_max, format, flags) || value_changed
	PopItemWidth()
	PopID()

	SameLine(0, g.Style.ItemInnerSpacing.x)
	TextEx(FindRenderedTextEnd(label), 0)

	EndGroup()
	return value_changed
}

func DragScalarInts(label string, data_type ImGuiDataType, p_data []int, v_speed float /*= 0*/, p_min *int /*= L*/, p_max *int /*= L*/, format string, flags ImGuiSliderFlags) bool {
	var window = GetCurrentWindow()
	if window.SkipItems {
		return false
	}

	var g = GImGui
	var value_changed = false
	BeginGroup()
	PushString(label)
	PushMultiItemsWidths(int(len(p_data)), CalcItemWidth())
	for i := range p_data {
		PushID(int(i))
		if i > 0 {
			SameLine(0, g.Style.ItemInnerSpacing.x)
		}
		value_changed = DragScalar("", data_type, &p_data[i], v_speed, p_min, p_max, format, flags) || value_changed
		PopID()
		PopItemWidth()
	}
	PopID()

	SameLine(0, g.Style.ItemInnerSpacing.x)
	TextEx(label, 0)

	EndGroup()
	return value_changed
}

// Convert a value v in the output space of a slider into a parametric position on the slider itself (the logical opposite of ScaleValueFromRatioT)
func ScaleRatioFromValueT(v, v_min, v_max float, is_logarithmic bool, logarithmic_zero_epsilon, zero_deadzone_halfsize float) float {
	if v_min == v_max {
		return 0.0
	}

	var v_clamped = ImClamp(v, v_max, v_min)
	if v_min < v_max {
		v_clamped = ImClamp(v, v_min, v_max)
	}
	if is_logarithmic {
		var flipped = v_max < v_min

		if flipped { // Handle the case where the range is backwards
			v_min, v_max = v_max, v_min
		}

		// Fudge min/max to avoid getting close to log(0)
		var v_min_fudged = v_min
		if ImAbs(v_min) < logarithmic_zero_epsilon {
			if v_min < 0.0 {
				v_min_fudged = -logarithmic_zero_epsilon
			} else {
				v_min_fudged = logarithmic_zero_epsilon
			}
		}
		var v_max_fudged = v_max
		if ImAbs(v_max) < logarithmic_zero_epsilon {
			if v_max < 0.0 {
				v_max_fudged = -logarithmic_zero_epsilon
			} else {
				v_max_fudged = logarithmic_zero_epsilon
			}
		}

		// Awkward special cases - we need ranges of the form (-100 .. 0) to convert to (-100 .. -epsilon), not (-100 .. epsilon)
		if (v_min == 0.0) && (v_max < 0.0) {
			v_min_fudged = -logarithmic_zero_epsilon
		} else if (v_max == 0.0) && (v_min < 0.0) {
			v_max_fudged = -logarithmic_zero_epsilon
		}

		var result float

		if v_clamped <= v_min_fudged {
			result = 0.0 // Workaround for values that are in-range but below our fudge
		} else if v_clamped >= v_max_fudged {
			result = 1.0 // Workaround for values that are in-range but above our fudge
		} else if (v_min * v_max) < 0.0 { // Range crosses zero, so split into two portions

			var zero_point_center = (-(float)(v_min)) / ((float)(v_max) - (float)(v_min)) // The zero point in parametric space.  There's an argument we should take the logarithmic nature into account when calculating this, but for now this should do (and the most common case of a symmetrical range works fine)
			var zero_point_snap_L = zero_point_center - zero_deadzone_halfsize
			var zero_point_snap_R = zero_point_center + zero_deadzone_halfsize
			if v == 0.0 {
				result = zero_point_center // Special case for exactly zero
			} else if v < 0.0 {
				result = (1.0 - (float)(ImLog(-v_clamped/logarithmic_zero_epsilon)/ImLog(-v_min_fudged/logarithmic_zero_epsilon))) * zero_point_snap_L
			} else {
				result = zero_point_snap_R + ((float)(ImLog(v_clamped/logarithmic_zero_epsilon)/ImLog(v_max_fudged/logarithmic_zero_epsilon)) * (1.0 - zero_point_snap_R))
			}
		} else if (v_min < 0.0) || (v_max < 0.0) { // Entirely negative slider
			result = 1.0 - (float)(ImLog(-v_clamped/-v_max_fudged)/ImLog(-v_min_fudged/-v_max_fudged))
		} else {
			result = (float)(ImLog(v_clamped/v_min_fudged) / ImLog(v_max_fudged/v_min_fudged))
		}
		if flipped {
			result = 1.0 - result
		}
		return result
	}

	// Linear slider
	return (v_clamped - v_min) / (v_max - v_min)
}

// Convert a parametric position on a slider into a value v in the output space (the logical opposite of ScaleRatioFromValueT)
func ScaleValueFromRatioT(t, v_min, v_max float, is_logarithmic bool, logarithmic_zero_epsilon, zero_deadzone_halfsize float) float {
	if v_min == v_max {
		return v_min
	}

	var is_floating_point = true

	var result float
	if is_logarithmic {
		// We special-case the extents because otherwise our fudging can lead to "mathematically correct" but non-intuitive behaviors like a fully-left slider not actually reaching the minimum value
		if t <= 0.0 {
			result = v_min
		} else if t >= 1.0 {
			result = v_max
		} else {
			var flipped = v_max < v_min // Check if range is "backwards"

			// Fudge min/max to avoid getting silly results close to zero
			var v_min_fudged = v_min
			if ImAbs(v_min) < logarithmic_zero_epsilon {
				if v_min < 0.0 {
					v_min_fudged = -logarithmic_zero_epsilon
				} else {
					v_min_fudged = logarithmic_zero_epsilon
				}
			}
			var v_max_fudged = v_max
			if ImAbs(v_max) < logarithmic_zero_epsilon {
				if v_max < 0.0 {
					v_min_fudged = -logarithmic_zero_epsilon
				} else {
					v_min_fudged = logarithmic_zero_epsilon
				}
			}

			if flipped {
				v_min_fudged, v_max_fudged = v_max_fudged, v_min_fudged
			}

			// Awkward special case - we need ranges of the form (-100 .. 0) to convert to (-100 .. -epsilon), not (-100 .. epsilon)
			if (v_max == 0.0) && (v_min < 0.0) {
				v_max_fudged = -logarithmic_zero_epsilon
			}

			var t_with_flip = t // t, but flipped if necessary to account for us flipping the range
			if flipped {
				t_with_flip = (1.0 - t)
			}

			if (v_min * v_max) < 0.0 { // Range crosses zero, so we have to do this in two parts
				var zero_point_center = (-ImMin(v_min, v_max)) / ImAbs(v_max-v_min) // The zero point in parametric space
				var zero_point_snap_L = zero_point_center - zero_deadzone_halfsize
				var zero_point_snap_R = zero_point_center + zero_deadzone_halfsize
				if t_with_flip >= zero_point_snap_L && t_with_flip <= zero_point_snap_R {
					result = 0.0 // Special case to make getting exactly zero possible (the epsilon prevents it otherwise)
				} else if t_with_flip < zero_point_center {
					result = -(logarithmic_zero_epsilon * ImPow(-v_min_fudged/logarithmic_zero_epsilon, (float)(1.0-(t_with_flip/zero_point_snap_L))))
				} else {
					result = (logarithmic_zero_epsilon * ImPow(v_max_fudged/logarithmic_zero_epsilon, (float)((t_with_flip-zero_point_snap_R)/(1.0-zero_point_snap_R))))
				}
			} else if (v_min < 0.0) || (v_max < 0.0) { // Entirely negative slider
				result = -(-v_max_fudged * ImPow(-v_min_fudged/-v_max_fudged, (float)(1.0-t_with_flip)))
			} else {
				result = (v_min_fudged * ImPow(v_max_fudged/v_min_fudged, (float)(t_with_flip)))
			}
		}
	} else {
		// Linear slider
		if is_floating_point {
			result = ImLerp(v_min, v_max, t)
		} else {
			// - For integer values we want the clicking position to match the grab box so we round above
			//   This code is carefully tuned to work with large values (e.g. high ranges of U64) while preserving this property..
			// - Not doing a *1.0 multiply at the end of a range as it tends to be lossy. While absolute aiming at a large s64/u64
			//   range is going to be imprecise anyway, with this check we at least make the edge values matches expected limits.
			if t < 1.0 {
				var v_new_off_f = (v_max - v_min) * t
				if v_min > v_max {
					result = v_min + (v_new_off_f + -0.5)
				} else {
					result = v_min + (v_new_off_f + 0.5)
				}
			} else {
				result = v_max
			}
		}
	}

	return result
}

func RoundScalarWithFormatT(format string, v float) float {
	// Format value with our rounding, and read back
	var v_str = fmt.Sprintf(format, v)
	f, _ := strconv.ParseFloat(v_str, 32)
	return float(f)
}

func DragBehaviorT(v *float, v_speed float, v_min, v_max *float, format string, flags ImGuiSliderFlags) bool {
	var g = GImGui
	var axis = ImGuiAxis_X
	if (flags & ImGuiSliderFlags_Vertical) != 0 {
		axis = ImGuiAxis_Y
	}
	var is_clamped = (*v_min < *v_max)
	var is_logarithmic = (flags & ImGuiSliderFlags_Logarithmic) != 0
	var is_floating_point = true

	// Default tweak speed
	if v_speed == 0.0 && is_clamped && (*v_max-*v_min < FLT_MAX) {
		v_speed = (float)((*v_max - *v_min) * g.DragSpeedDefaultRatio)
	}
	// Inputs accumulates into g.DragCurrentAccum, which is flushed into the current value as soon as it makes a difference with our precision settings
	var adjust_delta float
	if g.ActiveIdSource == ImGuiInputSource_Mouse && IsMousePosValid(nil) && IsMouseDragPastThreshold(0, g.IO.MouseDragThreshold*DRAG_MOUSE_THRESHOLD_FACTOR) {
		switch axis {
		case ImGuiAxis_X:
			adjust_delta *= g.IO.MouseDelta.x
		case ImGuiAxis_Y:
			adjust_delta *= g.IO.MouseDelta.y
		}
		if g.IO.KeyAlt {
			adjust_delta *= 1.0 / 100.0
		}
		if g.IO.KeyShift {
			adjust_delta *= 10.0
		}
	} else if g.ActiveIdSource == ImGuiInputSource_Nav {
		var decimal_precision int = 3
		amount := GetNavInputAmount2d(ImGuiNavDirSourceFlags_Keyboard|ImGuiNavDirSourceFlags_PadDPad, ImGuiInputReadMode_RepeatFast, 1.0/10.0, 10.0)
		switch axis {
		case ImGuiAxis_X:
			adjust_delta *= amount.x
		case ImGuiAxis_Y:
			adjust_delta *= amount.y
		}
		v_speed = ImMax(v_speed, GetMinimumStepAtDecimalPrecision(decimal_precision))
	}

	adjust_delta *= v_speed

	// For vertical drag we currently assume that Up=higher value (like we do with vertical sliders). This may become a parameter.
	if axis == ImGuiAxis_Y {
		adjust_delta = -adjust_delta
	}

	// For logarithmic use our range is effectively 0..1 so scale the delta into that range
	if is_logarithmic && (*v_max-*v_min < FLT_MAX) && ((*v_max - *v_min) > 0.000001) { // Epsilon to avoid /0
		adjust_delta /= (float)(*v_max - *v_min)
	}

	// Clear current value on activation
	// Avoid altering values and clamping when we are _already_ past the limits and heading in the same direction, so e.g. if range is 0..255, current value is 300 and we are pushing to the right side, keep the 300.
	var is_just_activated = g.ActiveIdIsJustActivated
	var is_already_past_limits_and_pushing_outward = is_clamped && ((*v >= *v_max && adjust_delta > 0.0) || (*v <= *v_min && adjust_delta < 0.0))
	if is_just_activated || is_already_past_limits_and_pushing_outward {
		g.DragCurrentAccum = 0.0
		g.DragCurrentAccumDirty = false
	} else if adjust_delta != 0.0 {
		g.DragCurrentAccum += adjust_delta
		g.DragCurrentAccumDirty = true
	}

	if !g.DragCurrentAccumDirty {
		return false
	}

	var v_cur = *v
	var v_old_ref_for_accum_remainder float

	var logarithmic_zero_epsilon float // Only valid when is_logarithmic is true
	var zero_deadzone_halfsize float   // Drag widgets have no deadzone (as it doesn't make sense)
	if is_logarithmic {
		// When using logarithmic sliders, we need to clamp to avoid hitting zero, but our choice of clamp value greatly affects slider precision. We attempt to use the specified precision to estimate a good lower bound.
		var decimal_precision = 3
		logarithmic_zero_epsilon = ImPow(0.1, (float)(decimal_precision))

		// Convert to parametric space, apply delta, convert back
		var v_old_parametric = ScaleRatioFromValueT(v_cur, *v_min, *v_max, is_logarithmic, logarithmic_zero_epsilon, zero_deadzone_halfsize)
		var v_new_parametric = v_old_parametric + g.DragCurrentAccum
		v_cur = ScaleValueFromRatioT(v_new_parametric, *v_min, *v_max, is_logarithmic, logarithmic_zero_epsilon, zero_deadzone_halfsize)
		v_old_ref_for_accum_remainder = v_old_parametric
	} else {
		v_cur += (float)(g.DragCurrentAccum)
	}

	// Round to user desired precision based on format string
	if flags&ImGuiSliderFlags_NoRoundToFormat == 0 {
		v_cur = RoundScalarWithFormatT(format, v_cur)
	}

	// Preserve remainder after rounding has been applied. This also allow slow tweaking of values.
	g.DragCurrentAccumDirty = false
	if is_logarithmic {
		// Convert to parametric space, apply delta, convert back
		var v_new_parametric = ScaleRatioFromValueT(v_cur, *v_min, *v_max, is_logarithmic, logarithmic_zero_epsilon, zero_deadzone_halfsize)
		g.DragCurrentAccum -= (float)(v_new_parametric - v_old_ref_for_accum_remainder)
	} else {
		g.DragCurrentAccum -= (float)(v_cur - *v)
	}

	// Lose zero sign for float/double
	if v_cur == (float)(-0) {
		v_cur = (float)(0)
	}

	// Clamp values (+ handle overflow/wrap-around for integer types)
	if *v != v_cur && is_clamped {
		if v_cur < *v_min || (v_cur > *v && adjust_delta < 0.0 && !is_floating_point) {
			v_cur = *v_min
		}
		if v_cur > *v_max || (v_cur < *v && adjust_delta > 0.0 && !is_floating_point) {
			v_cur = *v_max
		}
	}

	// Apply result
	if *v == v_cur {
		return false
	}

	*v = v_cur
	return true
}

func DragBehavior(id ImGuiID, data_type ImGuiDataType, v any, v_speed float, n any, x any, t string, flags ImGuiSliderFlags) bool {
	// Read imgui.cpp "API BREAKING CHANGES" section for 1.78 if you hit this assert.
	IM_ASSERT_USER_ERROR((flags == 1 || (flags&ImGuiSliderFlags_InvalidMask_) == 0), "Invalid ImGuiSliderFlags flags! Has the 'float power' argument been mistakenly cast to flags? Call function with ImGuiSliderFlags_Logarithmic flags instead.")

	var g = GImGui
	if g.ActiveId == id {
		if g.ActiveIdSource == ImGuiInputSource_Mouse && !g.IO.MouseDown[0] {
			ClearActiveID()
		} else if g.ActiveIdSource == ImGuiInputSource_Nav && g.NavActivatePressedId == id && !g.ActiveIdIsJustActivated {
			ClearActiveID()
		}
	}
	if g.ActiveId != id {
		return false
	}
	if (g.LastItemData.InFlags&ImGuiItemFlags_ReadOnly != 0) || (flags&ImGuiSliderFlags_ReadOnly != 0) {
		return false
	}

	// FIXME: this is kinda hacky, we can't just convert a float
	// interface to an int interface, but we can use reflection
	// to get the value as a float, pass it to DragBehaviourT,
	// and set the value back
	// convert v to float
	v_value := reflect.ValueOf(v).Elem()
	var v_float float
	if !v_value.CanFloat() {
		v_float = float(v_value.Int())
	} else {
		v_float = float(v_value.Float())
	}

	// convert n to float
	n_value := reflect.ValueOf(n).Elem()
	var n_float float
	if !n_value.CanFloat() {
		n_float = float(n_value.Int())
	} else {
		n_float = float(n_value.Float())
	}

	// convert x to float
	x_value := reflect.ValueOf(x).Elem()
	var x_float float
	if !x_value.CanFloat() {
		x_float = float(x_value.Int())
	} else {
		x_float = float(x_value.Float())
	}

	dragRet := DragBehaviorT(&v_float, v_speed, &n_float, &x_float, t, flags)

	// set new value of v
	if v_value.CanSet() {
		if v_value.CanFloat() {
			v_value.SetFloat(float64(v_float))
		} else {
			v_value.SetInt(int64(v_float))
		}
	}

	// set new value of n
	if n_value.CanSet() {
		if n_value.CanFloat() {
			n_value.SetFloat(float64(n_float))
		} else {
			n_value.SetInt(int64(n_float))
		}
	}

	// set new value of x
	if x_value.CanSet() {
		if x_value.CanFloat() {
			x_value.SetFloat(float64(x_float))
		} else {
			x_value.SetInt(int64(x_float))
		}
	}

	return dragRet
}