mirrors/imgui
1
Fork 0
mirror of https://github.com/ocornut/imgui.git synced 2024-10-16 16:25:15 -05:00
Code Issues Projects Releases Packages Wiki Activity Actions 1

MultiSelect: Demo: Assets Browser: track scrolling target so we can roughly land on hovered item.

Browse source 
It's impossible to do this perfectly without some form of locking on item because as the hovered item X position changes it's easy to drift.
This commit is contained in:
ocornut 2023-12-12 17:26:02 +01:00
parent 750e23998f
commit 7546a2d345
1 changed files with 76 additions and 38 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

96
imgui_demo.cpp
View file

@ -9634,6 +9634,15 @@ struct ExampleAssetsBrowser
bool RequestSort = false; // Deferred sort request
float ZoomWheelAccum = 0.0f; // Mouse wheel accumulator to handle smooth wheels better
// Calculated sizes for layout, output of UpdateLayoutSizes(). Could be locals but our code is simpler this way.
ImVec2 LayoutItemSize;
ImVec2 LayoutItemStep; // == LayoutItemSize + LayoutItemSpacing
float LayoutItemSpacing = 0.0f;
float LayoutSelectableSpacing = 0.0f;
float LayoutOuterPadding = 0.0f;
int LayoutColumnCount = 0;
int LayoutLineCount = 0;
// Functions
ExampleAssetsBrowser()
{
@ -9654,6 +9663,29 @@ struct ExampleAssetsBrowser
Selection.Clear();
}
// Logic would be written in the main code BeginChild() and outputing to local variables.
// We extracted it into a function so we can call it easily from multiple places.
void UpdateLayoutSizes(float avail_width)
{
// Layout: when not stretching: allow extending into right-most spacing.
LayoutItemSpacing = (float)IconSpacing;
if (StretchSpacing == false)
avail_width += floorf(LayoutItemSpacing * 0.5f);
// Layout: calculate number of icon per line and number of lines
LayoutItemSize = ImVec2(floorf(IconSize), floorf(IconSize));
LayoutColumnCount = IM_MAX((int)(avail_width / (LayoutItemSize.x + LayoutItemSpacing)), 1);
LayoutLineCount = (Items.Size + LayoutColumnCount - 1) / LayoutColumnCount;
// Layout: when stretching: allocate remaining space to more spacing. Round before division, so item_spacing may be non-integer.
if (StretchSpacing && LayoutColumnCount > 1)
LayoutItemSpacing = floorf(avail_width - LayoutItemSize.x * LayoutColumnCount) / LayoutColumnCount;
LayoutItemStep = ImVec2(LayoutItemSize.x + LayoutItemSpacing, LayoutItemSize.y + LayoutItemSpacing);
LayoutSelectableSpacing = IM_MAX(floorf(LayoutItemSpacing) - IconHitSpacing, 0.0f);
LayoutOuterPadding = floorf(LayoutItemSpacing * 0.5f);
}
void Draw(const char* title, bool* p_open)
{
ImGui::SetNextWindowSize(ImVec2(IconSize * 25, IconSize * 15), ImGuiCond_FirstUseEver);
@ -9722,27 +9754,18 @@ struct ExampleAssetsBrowser
}
ImGui::PopStyleVar();
if (ImGui::BeginChild("Assets", ImVec2(0, -ImGui::GetTextLineHeightWithSpacing()), true, ImGuiWindowFlags_NoMove))
ImGuiIO& io = ImGui::GetIO();
ImGui::SetNextWindowContentSize(ImVec2(0.0f, LayoutOuterPadding + LayoutLineCount * (LayoutItemSize.x + LayoutItemSpacing)));
if (ImGui::BeginChild("Assets", ImVec2(0.0f, -ImGui::GetTextLineHeightWithSpacing()), ImGuiChildFlags_Border, ImGuiWindowFlags_NoMove))
{
ImDrawList* draw_list = ImGui::GetWindowDrawList();
const ImVec2 item_size(floorf(IconSize), floorf(IconSize));
// Layout: when not stretching: allow extending into right-most spacing.
float item_spacing = (float)IconSpacing;
const float avail_width = ImGui::GetContentRegionAvail().x + (StretchSpacing ? 0.0f : floorf(item_spacing * 0.5f));
// Layout: calculate number of icon per line and number of lines
const int column_count = IM_MAX((int)(avail_width / (item_size.x + IconSpacing)), 1);
const int line_count = (Items.Size + column_count - 1) / column_count;
// Layout: when stretching: allocate remaining space to more spacing. Round before division, so item_spacing may be non-integer.
if (StretchSpacing && column_count > 1)
item_spacing = floorf(avail_width - item_size.x * column_count) / column_count;
const float avail_width = ImGui::GetContentRegionAvail().x;
UpdateLayoutSizes(avail_width);
// Calculate and store start position.
const float outer_padding = floorf(item_spacing * 0.5f);
ImVec2 start_pos = ImGui::GetCursorScreenPos();
start_pos = ImVec2(start_pos.x + outer_padding, start_pos.y + outer_padding);
start_pos = ImVec2(start_pos.x + LayoutOuterPadding, start_pos.y + LayoutOuterPadding);
ImGui::SetCursorScreenPos(start_pos);
// Multi-select
@ -9760,22 +9783,22 @@ struct ExampleAssetsBrowser
const int item_curr_idx_to_focus = want_delete ? Selection.ApplyDeletionPreLoop(ms_io, Items.Size) : -1;
RequestDelete = false;
// Altering ItemSpacing may seem unnecessary as we position every items using SetCursorScreenPos()...
// Push LayoutSelectableSpacing (which is LayoutItemSpacing minus hit-spacing, if we decide to have hit gaps between items)
// Altering style ItemSpacing may seem unnecessary as we position every items using SetCursorScreenPos()...
// But it is necessary for two reasons:
// - Selectables uses it by default to visually fill the space between two items.
// - The vertical spacing would be measured by Clipper to calculate line height if we didn't provide it explicitly (here we do).
const float selectable_spacing = IM_MAX(floorf(item_spacing) - IconHitSpacing, 0.0f);
ImGui::PushStyleVar(ImGuiStyleVar_ItemSpacing, ImVec2(selectable_spacing, selectable_spacing));
ImGui::PushStyleVar(ImGuiStyleVar_ItemSpacing, ImVec2(LayoutSelectableSpacing, LayoutSelectableSpacing));
// Rendering parameters
const ImU32 icon_bg_color = IM_COL32(48, 48, 48, 128);
const ImU32 icon_type_overlay_colors[3] = { 0, IM_COL32(200, 70, 70, 255), IM_COL32(70, 170, 70, 255) };
const ImVec2 icon_type_overlay_size = ImVec2(4.0f, 4.0f);
const bool display_label = (item_size.x >= ImGui::CalcTextSize("999").x);
const bool display_label = (LayoutItemSize.x >= ImGui::CalcTextSize("999").x);
const float line_height = item_size.y + item_spacing;
const int column_count = LayoutColumnCount;
ImGuiListClipper clipper;
clipper.Begin(line_count, line_height);
clipper.Begin(LayoutLineCount, LayoutItemStep.y);
if (item_curr_idx_to_focus != -1)
clipper.IncludeItemByIndex(item_curr_idx_to_focus / column_count); // Ensure focused item line is not clipped.
if (ms_io->RangeSrcItem != -1)
@ -9792,17 +9815,17 @@ struct ExampleAssetsBrowser
ImGui::PushID((int)item_data->ID);
// Position item
ImVec2 pos = ImVec2(start_pos.x + (item_idx % column_count) * (item_size.x + item_spacing), start_pos.y + (line_idx * line_height));
ImVec2 pos = ImVec2(start_pos.x + (item_idx % column_count) * LayoutItemStep.x, start_pos.y + line_idx * LayoutItemStep.y);
ImGui::SetCursorScreenPos(pos);
// Draw box
ImVec2 box_min(pos.x - 1, pos.y - 1);
ImVec2 box_max(box_min.x + item_size.x + 2, box_min.y + item_size.y + 2);
ImVec2 box_max(box_min.x + LayoutItemSize.x + 2, box_min.y + LayoutItemSize.y + 2);
draw_list->AddRect(box_min, box_max, IM_COL32(90, 90, 90, 255));
ImGui::SetNextItemSelectionUserData(item_idx);
bool item_is_selected = Selection.Contains((ImGuiID)item_data->ID);
ImGui::Selectable("", item_is_selected, ImGuiSelectableFlags_None, item_size);
ImGui::Selectable("", item_is_selected, ImGuiSelectableFlags_None, LayoutItemSize);
// Update our selection state immediately (without waiting for EndMultiSelect() requests)
// because we use this to alter the color of our text/icon.
@ -9865,11 +9888,8 @@ struct ExampleAssetsBrowser
// FIXME-MULTISELECT: Find a way to expose this in public API. This currently requires "imgui_internal.h"
//ImGui::NavMoveRequestTryWrapping(ImGui::GetCurrentWindow(), ImGuiNavMoveFlags_WrapX);
}
// Zooming with CTRL+Wheel
// FIXME-MULTISELECT: Try to maintain scroll.
ImGuiIO& io = ImGui::GetIO();
if (ImGui::IsWindowAppearing())
ZoomWheelAccum = 0.0f;
if (ImGui::IsWindowHovered() && io.MouseWheel != 0.0f && ImGui::IsKeyDown(ImGuiMod_Ctrl) && ImGui::IsAnyItemActive() == false)
@ -9877,13 +9897,31 @@ struct ExampleAssetsBrowser
ZoomWheelAccum += io.MouseWheel;
if (fabsf(ZoomWheelAccum) >= 1.0f)
{
// Calculate hovered item index from mouse location
// FIXME: Locking aiming on 'hovered_item_idx' (with a cool-down timer) would ensure zoom keeps on it.
const float hovered_item_nx = (io.MousePos.x - start_pos.x + LayoutItemSpacing * 0.5f) / LayoutItemStep.x;
const float hovered_item_ny = (io.MousePos.y - start_pos.y + LayoutItemSpacing * 0.5f) / LayoutItemStep.y;
const int hovered_item_idx = ((int)hovered_item_ny * LayoutColumnCount) + (int)hovered_item_nx;
//ImGui::SetTooltip("%f,%f -> item %d", hovered_item_nx, hovered_item_ny, hovered_item_idx); // Move those 4 lines in block above for easy debugging
// Zoom
IconSize *= powf(1.1f, (float)(int)ZoomWheelAccum);
IconSize = IM_CLAMP(IconSize, 16.0f, 128.0f);
ZoomWheelAccum -= (int)ZoomWheelAccum;
}
}
UpdateLayoutSizes(avail_width);
// Manipulate scroll to that we will land at the same Y location of currently hovered item.
// - Calculate next frame position of item under mouse
// - Set new scroll position to be used in next ImGui::BeginChild() call.
float hovered_item_rel_pos_y = ((float)(hovered_item_idx / LayoutColumnCount) + fmodf(hovered_item_ny, 1.0f)) * LayoutItemStep.y;
hovered_item_rel_pos_y += ImGui::GetStyle().WindowPadding.y;
float mouse_local_y = io.MousePos.y - ImGui::GetWindowPos().y;
ImGui::SetScrollY(hovered_item_rel_pos_y - mouse_local_y);
}
}
}
ImGui::EndChild();
ImGui::Text("Selected: %d/%d items", Selection.Size, Items.Size);
ImGui::End();
}