🚧 (broken) Window, Clipper: store initial precision loss and apply in…

… clipper. (#3609, #3962 + ocornut/imgui_club#20)
kotlin-graphics · Jan 28, 2023 · a487f09 · a487f09
1 parent 9ddd0a2
commit a487f09
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Showing 5 changed files with 16 additions and 8 deletions.
diff --git a/core/src/main/kotlin/imgui/api/windows.kt b/core/src/main/kotlin/imgui/api/windows.kt
@@ -2,6 +2,7 @@ package imgui.api
 
 import gli_.has
 import gli_.hasnt
+import glm_.d
 import glm_.f
 import glm_.max
 import glm_.vec2.Vec2
@@ -10,7 +11,6 @@ import imgui.ImGui.endColumns
 import imgui.ImGui.findBestWindowPosForPopup
 import imgui.ImGui.findWindowByName
 import imgui.ImGui.focusWindow
-import imgui.ImGui.getColorU32
 import imgui.ImGui.io
 import imgui.ImGui.isMouseHoveringRect
 import imgui.ImGui.logFinish
@@ -20,7 +20,6 @@ import imgui.ImGui.popClipRect
 import imgui.ImGui.pushClipRect
 import imgui.ImGui.setLastItemData
 import imgui.ImGui.style
-import imgui.ImGui.topMostPopupModal
 import imgui.internal.classes.Rect
 import imgui.internal.classes.WindowStackData
 import imgui.internal.floor
@@ -573,8 +572,13 @@ interface windows {
                 dc.indent = 0f + windowPadding.x - scroll.x
                 dc.groupOffset = 0f
                 dc.columnsOffset = 0f
-                dc.cursorStartPos.put(pos.x + dc.indent + dc.columnsOffset,
-                                      pos.y + decorationUpHeight + windowPadding.y - scroll.y)
+
+                // Record the loss of precision of CursorStartPos which can happen due to really large scrolling amount.
+                // This is used by clipper to compensate and fix the most common use case of large scroll area. Easy and cheap, next best thing compared to switching everything to double or ImU64.
+                val startPosHighpX = window.pos.x.d + window.windowPadding.x - window.scroll.x.d + window.dc.columnsOffset
+                val startPosHighpY = window.pos.y.d + window.windowPadding.y - window.scroll.y.d + decorationUpHeight
+                window.dc.cursorStartPos = Vec2(startPosHighpX, startPosHighpY)
+                window.dc.cursorStartPosLossyness.put(startPosHighpX - window.dc.cursorStartPos.x, startPosHighpY - window.dc.cursorStartPos.y)
                 dc.cursorPos put dc.cursorStartPos
                 dc.cursorPosPrevLine put dc.cursorPos
                 dc.cursorMaxPos put dc.cursorStartPos

diff --git a/core/src/main/kotlin/imgui/classes/ListClipper.kt b/core/src/main/kotlin/imgui/classes/ListClipper.kt
@@ -69,6 +69,7 @@ class ListClipper {
                 g.clipperTempData += ListClipperData()
         val data = g.clipperTempData[g.clipperTempDataStacked - 1]
         data.reset(this)
+        data.lossynessOffset = window.dc.cursorStartPosLossyness.y
         tempData = data
     }
 
@@ -188,8 +189,8 @@ class ListClipper {
             //   which with the flooring/ceiling tend to lead to 2 items instead of one being submitted.
             for (i in data.ranges.indices)
                 if (data.ranges[i].posToIndexConvert) {
-                    val m1 = ((data.ranges[i].min.d - window.dc.cursorPos.y) / itemsHeight).i
-                    val m2 = (((data.ranges[i].max.d - window.dc.cursorPos.y) / itemsHeight) + 0.999999f).i
+                    val m1 = ((data.ranges[i].min.d - window.dc.cursorPos.y - data.lossynessOffset) / itemsHeight).i
+                    val m2 = (((data.ranges[i].max.d - window.dc.cursorPos.y - data.lossynessOffset) / itemsHeight) + 0.999999f).i
                     data.ranges[i].min = clamp(alreadySubmitted + m1 + floor((data.ranges[i].min - window.dc.cursorPos.y) / itemsHeight).i + data.ranges[i].posToIndexOffsetMin, alreadySubmitted, itemsCount - 1)
                     data.ranges[i].max = clamp(alreadySubmitted + m2 + ceil((data.ranges[i].max - window.dc.cursorPos.y) / itemsHeight).i + 0 + data.ranges[i].posToIndexOffsetMax, data.ranges[i].min + 1, itemsCount)
                     data.ranges[i].posToIndexConvert = false
@@ -245,7 +246,7 @@ class ListClipper {
             // StartPosY starts from ItemsFrozen hence the subtraction
             // Perform the add and multiply with double to allow seeking through larger ranges
             val data = clipper.tempData as ListClipperData
-            val posY = (clipper.startPosY.d + (itemN - data.itemsFrozen).d * clipper.itemsHeight).f
+            val posY = (clipper.startPosY.d + data.lossynessOffset + (itemN - data.itemsFrozen).d * clipper.itemsHeight).f
             seekCursorAndSetupPrevLine(posY, clipper.itemsHeight)
         }
 

diff --git a/core/src/main/kotlin/imgui/imgui.kt b/core/src/main/kotlin/imgui/imgui.kt
@@ -17,7 +17,7 @@ const val IMGUI_VERSION_BUILD = "$IMGUI_VERSION.$IMGUI_BUILD"
 
 /** Integer encoded as XYYZZ for use in #if preprocessor conditionals.
 Work in progress versions typically starts at XYY99 then bounce up to XYY00, XYY01 etc. when release tagging happens) */
-const val IMGUI_VERSION_NUM = 18514
+const val IMGUI_VERSION_NUM = 18515
 
 
 // Helpers macros to generate 32-bits encoded colors

diff --git a/core/src/main/kotlin/imgui/internal/classes/WindowTempData.kt b/core/src/main/kotlin/imgui/internal/classes/WindowTempData.kt
@@ -48,6 +48,8 @@ class WindowTempData {
 
     var groupOffset = 0f
 
+    /** Record the loss of precision of CursorStartPos due to really large scrolling amount. This is used by clipper to compensentate and fix the most common use case of large scroll area. */
+    val cursorStartPosLossyness = Vec2()
 
     // Keyboard/Gamepad navigation
 

diff --git a/core/src/main/kotlin/imgui/internal/sections/Clipper support.kt b/core/src/main/kotlin/imgui/internal/sections/Clipper support.kt
@@ -24,6 +24,7 @@ class ListClipperRange {
 // Temporary clipper data, buffers shared/reused between instances
 class ListClipperData {
     lateinit var listClipper: ListClipper
+    var lossynessOffset = 0f
     var stepNo = 0
     var itemsFrozen = 0
     val ranges = ArrayList<ListClipperRange>()