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emacs-style movememnts and page up / down.

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Kyle Isom
2025-11-29 20:56:21 -08:00
parent f7c6e3db9f
commit f9606626b4
10 changed files with 324 additions and 164 deletions
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105
GUIRenderer.cc
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@@ -56,40 +56,77 @@ GUIRenderer::Draw(Editor &ed)
const float line_h = ImGui::GetTextLineHeight();
const float row_h = ImGui::GetTextLineHeightWithSpacing();
const float space_w = ImGui::CalcTextSize(" ").x;
// When the user scrolls and the cursor is off-screen, move it to the nearest visible row
{
static float prev_scroll_y = -1.0f;
float child_h = ImGui::GetWindowHeight(); // child window height
long first_row = static_cast<long>(scroll_y / row_h);
long vis_rows = static_cast<long>(child_h / row_h);
if (vis_rows < 1)
vis_rows = 1;
long last_row = first_row + vis_rows - 1;
if (prev_scroll_y >= 0.0f && scroll_y != prev_scroll_y) {
long cyr = static_cast<long>(cy);
if (cyr < first_row || cyr > last_row) {
long new_row = (cyr < first_row) ? first_row : last_row;
if (new_row < 0)
new_row = 0;
if (new_row >= static_cast<long>(lines.size())) {
new_row = static_cast<long>(lines.empty() ? 0 : (lines.size() - 1));
}
// Clamp column to line length
std::size_t new_col = 0;
if (!lines.empty()) {
const std::string &l = lines[static_cast<std::size_t>(new_row)];
new_col = std::min<std::size_t>(cx, l.size());
}
char tmp2[64];
std::snprintf(tmp2, sizeof(tmp2), "%ld:%zu", new_row, new_col);
Execute(ed, CommandId::MoveCursorTo, std::string(tmp2));
// refresh local variables after move
cy = buf->Cury();
cx = buf->Curx();
}
}
prev_scroll_y = scroll_y;
}
// If the command layer requested a specific top-of-screen (via Buffer::Rowoffs),
// force the ImGui scroll to match so paging aligns the first visible row.
bool forced_scroll = false;
{
std::size_t desired_top = buf->Rowoffs();
long current_top = static_cast<long>(scroll_y / row_h);
if (static_cast<long>(desired_top) != current_top) {
ImGui::SetScrollY(static_cast<float>(desired_top) * row_h);
scroll_y = ImGui::GetScrollY();
forced_scroll = true;
}
}
// Synchronize cursor and scrolling.
// A) When the user scrolls and the cursor goes off-screen, move the cursor to the nearest visible row.
// B) When the cursor moves (via keyboard commands), scroll it back into view.
{
static float prev_scroll_y = -1.0f;
static long prev_cursor_y = -1;
// Compute visible row range using the child window height
float child_h = ImGui::GetWindowHeight();
long first_row = static_cast<long>(scroll_y / row_h);
long vis_rows = static_cast<long>(child_h / row_h);
if (vis_rows < 1) vis_rows = 1;
long last_row = first_row + vis_rows - 1;
// A) If user scrolled (scroll_y changed), and cursor outside, move cursor to nearest visible row
if (prev_scroll_y >= 0.0f && scroll_y != prev_scroll_y) {
long cyr = static_cast<long>(cy);
if (cyr < first_row || cyr > last_row) {
long new_row = (cyr < first_row) ? first_row : last_row;
if (new_row < 0) new_row = 0;
if (new_row >= static_cast<long>(lines.size()))
new_row = static_cast<long>(lines.empty() ? 0 : (lines.size() - 1));
// Clamp column to line length
std::size_t new_col = 0;
if (!lines.empty()) {
const std::string &l = lines[static_cast<std::size_t>(new_row)];
new_col = std::min<std::size_t>(cx, l.size());
}
char tmp2[64];
std::snprintf(tmp2, sizeof(tmp2), "%ld:%zu", new_row, new_col);
Execute(ed, CommandId::MoveCursorTo, std::string(tmp2));
cy = buf->Cury();
cx = buf->Curx();
cyr = static_cast<long>(cy);
// Update visible range again in case content changed
first_row = static_cast<long>(ImGui::GetScrollY() / row_h);
last_row = first_row + vis_rows - 1;
}
}
// B) If cursor moved since last frame and is outside the visible region, scroll to reveal it
// Skip this when we just forced a top-of-screen alignment this frame.
if (!forced_scroll && prev_cursor_y >= 0 && static_cast<long>(cy) != prev_cursor_y) {
long cyr = static_cast<long>(cy);
if (cyr < first_row || cyr > last_row) {
float target = (static_cast<float>(cyr) - std::max(0L, vis_rows / 2)) * row_h;
float max_y = ImGui::GetScrollMaxY();
if (target < 0.f) target = 0.f;
if (max_y >= 0.f && target > max_y) target = max_y;
ImGui::SetScrollY(target);
// refresh local variables
scroll_y = ImGui::GetScrollY();
first_row = static_cast<long>(scroll_y / row_h);
last_row = first_row + vis_rows - 1;
}
}
prev_scroll_y = ImGui::GetScrollY();
prev_cursor_y = static_cast<long>(cy);
}
// Handle mouse click before rendering to avoid dependent on drawn items
if (ImGui::IsWindowHovered() && ImGui::IsMouseClicked(ImGuiMouseButton_Left)) {
ImVec2 mp = ImGui::GetIO().MousePos;