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Demo: Fixed Log & Console from losing scrolling position with Auto-Sc…
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…roll when child is clipped. (ocornut#5721)
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@ocornut
ocornut committed Sep 28, 2022
1 parent 12c0246 commit 5c4426c
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1 change: 1 addition & 0 deletions docs/CHANGELOG.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -149,6 +149,7 @@ Other Changes:
- Docs: Fixed various typos in comments and documentations. (#5649, #5675, #5679) [@tocic, @lessigsx]
- Demo: Improved "Constrained-resizing window" example, more clearly showcase aspect-ratio. (#5627)
- Demo: Added more explicit "Center window" mode to "Overlay example". (#5618)
- Demo: Fixed Log & Console from losing scrolling position with Auto-Scroll when child is clipped. (#5721)
- Examples: Added all SDL examples to default VS solution.
- Backends: GLFW: Honor GLFW_CURSOR_DISABLED by not setting mouse position. (#5625) [@scorpion-26]
- Backends: SDL: Disable SDL 2.0.22 new "auto capture" which prevents drag and drop across windows
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211 changes: 107 additions & 104 deletions imgui_demo.cpp
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Expand Up @@ -6664,66 +6664,68 @@ struct ExampleAppConsole

// Reserve enough left-over height for 1 separator + 1 input text
const float footer_height_to_reserve = ImGui::GetStyle().ItemSpacing.y + ImGui::GetFrameHeightWithSpacing();
ImGui::BeginChild("ScrollingRegion", ImVec2(0, -footer_height_to_reserve), false, ImGuiWindowFlags_HorizontalScrollbar);
if (ImGui::BeginPopupContextWindow())
if (ImGui::BeginChild("ScrollingRegion", ImVec2(0, -footer_height_to_reserve), false, ImGuiWindowFlags_HorizontalScrollbar))
{
if (ImGui::Selectable("Clear")) ClearLog();
ImGui::EndPopup();
}
if (ImGui::BeginPopupContextWindow())
{
if (ImGui::Selectable("Clear")) ClearLog();
ImGui::EndPopup();
}

// Display every line as a separate entry so we can change their color or add custom widgets.
// If you only want raw text you can use ImGui::TextUnformatted(log.begin(), log.end());
// NB- if you have thousands of entries this approach may be too inefficient and may require user-side clipping
// to only process visible items. The clipper will automatically measure the height of your first item and then
// "seek" to display only items in the visible area.
// To use the clipper we can replace your standard loop:
// for (int i = 0; i < Items.Size; i++)
// With:
// ImGuiListClipper clipper;
// clipper.Begin(Items.Size);
// while (clipper.Step())
// for (int i = clipper.DisplayStart; i < clipper.DisplayEnd; i++)
// - That your items are evenly spaced (same height)
// - That you have cheap random access to your elements (you can access them given their index,
// without processing all the ones before)
// You cannot this code as-is if a filter is active because it breaks the 'cheap random-access' property.
// We would need random-access on the post-filtered list.
// A typical application wanting coarse clipping and filtering may want to pre-compute an array of indices
// or offsets of items that passed the filtering test, recomputing this array when user changes the filter,
// and appending newly elements as they are inserted. This is left as a task to the user until we can manage
// to improve this example code!
// If your items are of variable height:
// - Split them into same height items would be simpler and facilitate random-seeking into your list.
// - Consider using manual call to IsRectVisible() and skipping extraneous decoration from your items.
ImGui::PushStyleVar(ImGuiStyleVar_ItemSpacing, ImVec2(4, 1)); // Tighten spacing
if (copy_to_clipboard)
ImGui::LogToClipboard();
for (int i = 0; i < Items.Size; i++)
{
const char* item = Items[i];
if (!Filter.PassFilter(item))
continue;
// Display every line as a separate entry so we can change their color or add custom widgets.
// If you only want raw text you can use ImGui::TextUnformatted(log.begin(), log.end());
// NB- if you have thousands of entries this approach may be too inefficient and may require user-side clipping
// to only process visible items. The clipper will automatically measure the height of your first item and then
// "seek" to display only items in the visible area.
// To use the clipper we can replace your standard loop:
// for (int i = 0; i < Items.Size; i++)
// With:
// ImGuiListClipper clipper;
// clipper.Begin(Items.Size);
// while (clipper.Step())
// for (int i = clipper.DisplayStart; i < clipper.DisplayEnd; i++)
// - That your items are evenly spaced (same height)
// - That you have cheap random access to your elements (you can access them given their index,
// without processing all the ones before)
// You cannot this code as-is if a filter is active because it breaks the 'cheap random-access' property.
// We would need random-access on the post-filtered list.
// A typical application wanting coarse clipping and filtering may want to pre-compute an array of indices
// or offsets of items that passed the filtering test, recomputing this array when user changes the filter,
// and appending newly elements as they are inserted. This is left as a task to the user until we can manage
// to improve this example code!
// If your items are of variable height:
// - Split them into same height items would be simpler and facilitate random-seeking into your list.
// - Consider using manual call to IsRectVisible() and skipping extraneous decoration from your items.
ImGui::PushStyleVar(ImGuiStyleVar_ItemSpacing, ImVec2(4, 1)); // Tighten spacing
if (copy_to_clipboard)
ImGui::LogToClipboard();
for (int i = 0; i < Items.Size; i++)
{
const char* item = Items[i];
if (!Filter.PassFilter(item))
continue;

// Normally you would store more information in your item than just a string.
// (e.g. make Items[] an array of structure, store color/type etc.)
ImVec4 color;
bool has_color = false;
if (strstr(item, "[error]")) { color = ImVec4(1.0f, 0.4f, 0.4f, 1.0f); has_color = true; }
else if (strncmp(item, "# ", 2) == 0) { color = ImVec4(1.0f, 0.8f, 0.6f, 1.0f); has_color = true; }
if (has_color)
ImGui::PushStyleColor(ImGuiCol_Text, color);
ImGui::TextUnformatted(item);
if (has_color)
ImGui::PopStyleColor();
}
if (copy_to_clipboard)
ImGui::LogFinish();
// Normally you would store more information in your item than just a string.
// (e.g. make Items[] an array of structure, store color/type etc.)
ImVec4 color;
bool has_color = false;
if (strstr(item, "[error]")) { color = ImVec4(1.0f, 0.4f, 0.4f, 1.0f); has_color = true; }
else if (strncmp(item, "# ", 2) == 0) { color = ImVec4(1.0f, 0.8f, 0.6f, 1.0f); has_color = true; }
if (has_color)
ImGui::PushStyleColor(ImGuiCol_Text, color);
ImGui::TextUnformatted(item);
if (has_color)
ImGui::PopStyleColor();
}
if (copy_to_clipboard)
ImGui::LogFinish();

if (ScrollToBottom || (AutoScroll && ImGui::GetScrollY() >= ImGui::GetScrollMaxY()))
ImGui::SetScrollHereY(1.0f);
ScrollToBottom = false;
if (ScrollToBottom || (AutoScroll && ImGui::GetScrollY() >= ImGui::GetScrollMaxY()))
ImGui::SetScrollHereY(1.0f);
ScrollToBottom = false;

ImGui::PopStyleVar();
ImGui::PopStyleVar();
}
ImGui::EndChild();
ImGui::Separator();

Expand Down Expand Up @@ -6971,63 +6973,64 @@ struct ExampleAppLog
Filter.Draw("Filter", -100.0f);

ImGui::Separator();
ImGui::BeginChild("scrolling", ImVec2(0, 0), false, ImGuiWindowFlags_HorizontalScrollbar);

if (clear)
Clear();
if (copy)
ImGui::LogToClipboard();

ImGui::PushStyleVar(ImGuiStyleVar_ItemSpacing, ImVec2(0, 0));
const char* buf = Buf.begin();
const char* buf_end = Buf.end();
if (Filter.IsActive())
{
// In this example we don't use the clipper when Filter is enabled.
// This is because we don't have random access to the result of our filter.
// A real application processing logs with ten of thousands of entries may want to store the result of
// search/filter.. especially if the filtering function is not trivial (e.g. reg-exp).
for (int line_no = 0; line_no < LineOffsets.Size; line_no++)
{
const char* line_start = buf + LineOffsets[line_no];
const char* line_end = (line_no + 1 < LineOffsets.Size) ? (buf + LineOffsets[line_no + 1] - 1) : buf_end;
if (Filter.PassFilter(line_start, line_end))
ImGui::TextUnformatted(line_start, line_end);
}
}
else
if (ImGui::BeginChild("scrolling", ImVec2(0, 0), false, ImGuiWindowFlags_HorizontalScrollbar))
{
// The simplest and easy way to display the entire buffer:
// ImGui::TextUnformatted(buf_begin, buf_end);
// And it'll just work. TextUnformatted() has specialization for large blob of text and will fast-forward
// to skip non-visible lines. Here we instead demonstrate using the clipper to only process lines that are
// within the visible area.
// If you have tens of thousands of items and their processing cost is non-negligible, coarse clipping them
// on your side is recommended. Using ImGuiListClipper requires
// - A) random access into your data
// - B) items all being the same height,
// both of which we can handle since we have an array pointing to the beginning of each line of text.
// When using the filter (in the block of code above) we don't have random access into the data to display
// anymore, which is why we don't use the clipper. Storing or skimming through the search result would make
// it possible (and would be recommended if you want to search through tens of thousands of entries).
ImGuiListClipper clipper;
clipper.Begin(LineOffsets.Size);
while (clipper.Step())
{
for (int line_no = clipper.DisplayStart; line_no < clipper.DisplayEnd; line_no++)
if (clear)
Clear();
if (copy)
ImGui::LogToClipboard();

ImGui::PushStyleVar(ImGuiStyleVar_ItemSpacing, ImVec2(0, 0));
const char* buf = Buf.begin();
const char* buf_end = Buf.end();
if (Filter.IsActive())
{
// In this example we don't use the clipper when Filter is enabled.
// This is because we don't have random access to the result of our filter.
// A real application processing logs with ten of thousands of entries may want to store the result of
// search/filter.. especially if the filtering function is not trivial (e.g. reg-exp).
for (int line_no = 0; line_no < LineOffsets.Size; line_no++)
{
const char* line_start = buf + LineOffsets[line_no];
const char* line_end = (line_no + 1 < LineOffsets.Size) ? (buf + LineOffsets[line_no + 1] - 1) : buf_end;
ImGui::TextUnformatted(line_start, line_end);
if (Filter.PassFilter(line_start, line_end))
ImGui::TextUnformatted(line_start, line_end);
}
}
clipper.End();
}
ImGui::PopStyleVar();

if (AutoScroll && ImGui::GetScrollY() >= ImGui::GetScrollMaxY())
ImGui::SetScrollHereY(1.0f);
else
{
// The simplest and easy way to display the entire buffer:
// ImGui::TextUnformatted(buf_begin, buf_end);
// And it'll just work. TextUnformatted() has specialization for large blob of text and will fast-forward
// to skip non-visible lines. Here we instead demonstrate using the clipper to only process lines that are
// within the visible area.
// If you have tens of thousands of items and their processing cost is non-negligible, coarse clipping them
// on your side is recommended. Using ImGuiListClipper requires
// - A) random access into your data
// - B) items all being the same height,
// both of which we can handle since we have an array pointing to the beginning of each line of text.
// When using the filter (in the block of code above) we don't have random access into the data to display
// anymore, which is why we don't use the clipper. Storing or skimming through the search result would make
// it possible (and would be recommended if you want to search through tens of thousands of entries).
ImGuiListClipper clipper;
clipper.Begin(LineOffsets.Size);
while (clipper.Step())
{
for (int line_no = clipper.DisplayStart; line_no < clipper.DisplayEnd; line_no++)
{
const char* line_start = buf + LineOffsets[line_no];
const char* line_end = (line_no + 1 < LineOffsets.Size) ? (buf + LineOffsets[line_no + 1] - 1) : buf_end;
ImGui::TextUnformatted(line_start, line_end);
}
}
clipper.End();
}
ImGui::PopStyleVar();

if (AutoScroll && ImGui::GetScrollY() >= ImGui::GetScrollMaxY())
ImGui::SetScrollHereY(1.0f);
}
ImGui::EndChild();
ImGui::End();
}
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